all menu items should have a default SVG. Template authors then can
decide if they want to use them or not.

These are only the page tool SVGs. More need to be added.

I used svgo to strip all unneeded cruft from the svgs

Now any arbitrary attributes can be passed as 4th argument. This way
classes etc could be added by plugins.

This will open up the discussion from #236 again and I'm not sure how to
solve this best.

The TEMPLATE_PAGETOOLS_DISPLAY event is very specific to the dokuwiki
template in theory. In practice many other templates implemented not
only the same event but also use the same HTML (and often even the same
CSS). Which makes the event more like a core event.

This branch now changes the HTML the event expects back from handlers.
When merged it would immeadiately break all plugins implementing this
event (and by broken I mean the layout/design of the template breaks).

Since the expected data changes, I would argue this should be a new
event or at least be implemented in a way to not break the design by
installing an old plugin and by giving the plugin a chance to know if
it's running on the old or the new code.

This is what this commit does. By changing the view names, old plugins
should not display (because they hopefull do not handle those views) but
gives them an easy way to handle the old and new views in one plugin.

However, I'm not perfectly happy with it, yet.

The way I implemented the new SVG handling is by means of a new class
dokuwiki\template\dokuwiki\tpl which provides a pageToolAction() method.
Plugins could use this method to easily return the proper HTML for the
pagetool items and we could adjust this method later on to make
adjustments to the pagetools without breaking anything again.

However this method is template specific again. While it would possible
for plugins to use this method even when the wiki runs another plugin
emitting the event, it would be a bit weird.

A better way would be for the event to not expect HTML at all, but
instead a data structure of the data currently passed to
pageToolAction(). Templates could then decide to implement the event,
but still render the data in a completely different way...

OTOH this means plugins are no longer free to add whatever they want
into the pagetools. We once argued plugins might want to add submenus or
other fancy stuff there. But in fact no plugin ever did.

If we decide to go this new way of making the event more of a first
class citizen of template development, then we would probably have to
move parts or all of the tpl class back to the core.

The whole pagetool items are now build in an extra helper class that can
be reused by plugins.

todos:

* edit action (and maybe others) use different icons depending on state,
  we can't rely on passing $post
* media details screen not adjusted, yet
* no RTL styles
* no focus/active styles
* the event needs to be adjusted (maybe throw it away and do a new one)
* some icons are not good (create = edit)
* possibly more

* use inline-block instead of flexbox
* fix RTL alignments

This introduces an embedSVG() function that can be used at other places.

Squashed commit of the following:

commit 86183b66c5b53b47e5ddb1e0d1c155c06c331d35
Merge: ebfb1ab1 4a8f4288e
Author: Andreas Gohr <andi@splitbrain.org>
Date:   Sat Jan 21 11:20:32 2017 +0100

    Merge branch 'master' of git://github.com/ThisNameIsNotAllowed/dokuwiki into pull-request-1767

    * 'master' of git://github.com/ThisNameIsNotAllowed/dokuwiki:
      Update admin.php
      Update admin.php
      Update _admin.css
      Update admin.php
      Update html.php
      Update _admin.css
      Update html.php
      Update html.php
      Update html.php
      Update.html
      Update html.php
      Update admin.php

commit 4a8f4288e61d48156bf9c4a7c49756912e4dac25
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Fri Jan 20 09:25:52 2017 +0100

    Update admin.php

    Changed the code to check for icons being SVG files.
    This should fix php5.3 errors for using method returns straight on.

commit e43b6cae1e12c1d24efae301e6b25f79a660f353
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Fri Jan 20 08:22:41 2017 +0100

    Update admin.php

    Removed elements that could lead to behaviors that shouldn't occure.

commit 9af82fb6f43a5ce10ba9b54f1d5f5cac644c7611
Merge: b99c67797 0b8d1871c
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Thu Jan 19 16:22:02 2017 +0100

    Merge pull request #1 from ThisNameIsNotAllowed/add-c

    Added css, forced the author to use ".svg"-files for plugin icons.

commit 0b8d1871c8bd0a02aca3ff56128465e8739c96ea
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Thu Jan 19 16:17:34 2017 +0100

    Update _admin.css

    fixed some aligning for plugin names.

commit 9158649de99867574471a2b894f8611bb99b9a7f
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Thu Jan 19 15:49:20 2017 +0100

    Update admin.php

    Added method to return menu icons only in case their mime type matches svg files.

    Added warning to getMenuIcon comments telling the user to provide svg only.

commit 6df4e0f41880d40f0e7b1882d26fc647d6d2188e
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Thu Jan 19 15:46:17 2017 +0100

    Update html.php

    Added code to accept svg files only.
    Also changed names of css classes to suit dokuwiki style.

commit 3435abc52ac1dbd4e0cea291a8b30bef722638a6
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Thu Jan 19 15:41:06 2017 +0100

    Update _admin.css

    Added css for displaying plugin icons.

commit b99c67797eafdb73351f62d2db4c206426b9f828
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Thu Nov 24 14:16:23 2016 +0100

    Update html.php

    Changed the list of admin plugins.

    The icons and plugin names appearance can now be influenced by css.

commit 479c6517ff6fc6010c24b2a285249f3600bc3248
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Thu Nov 24 13:45:08 2016 +0100

    Update html.php

    Cleaned, due to too much duplicated code.

commit e621fd9788c064cc22385cfa4999a9be588bedc2
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Wed Nov 23 16:26:14 2016 +0100

    Update html.php

    Changed class name for images shown before plugin names.

commit 9099dac8483fc1aa5a875755ba3dea6e7eb3f280
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Wed Nov 23 16:24:01 2016 +0100

    Update.html

    Added icon to plugin array

commit faea3ceb7986ecd6d6bad3d8055a388f3810c4b1
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Wed Nov 23 15:56:40 2016 +0100

    Update html.php

    Added support to display plugin icons in admin menu.

commit 539e60be075ab060d7d57beadc74d94606262a2e
Author: ThisNameIsNotAllowed <ThisNameIsNotAllowed@users.noreply.github.com>
Date:   Wed Nov 23 15:51:39 2016 +0100

    Update admin.php

    Add support for icons in admin menu.

The bind() call is deprecated in jQuery 3. This replaces it with
the on() call.

jQuery UI replaced the buttonset widget with a controlgroup widget. This
adjusts the JavaScript and styling accordingly.

If using a west handle, jQuery UI Resizable uses left offset to
position, assuming relative:absolute like setup.

- http://stackoverflow.com/questions/28512111/resizable-div-that-
doesnt-change-left-property
- https://bugs.jqueryui.com/ticket/4985#comment:1