This applies a lot of formatting fixes on the language files:

1. In EOF - trimmed all empty lines except one
2. After the title - one empty line strictly
3. Corrected links to national versions of documents in dokuwiki.org if
   they exits - 4example [[doku>namespaces]] to [[doku>ar:namespaces]]
4. Corrected some over-auto-translated links to "playground:playground"
   and "wiki:syntax"
5. Torn lines are collected in one in a large number of places (except
   for RTL languages)
6. Removed e-mail signatures that now is missing in the English set of
   files

- jQuery to 3.1.1
- jQuery UI to 1.12.1
- jQuery Migrate to 3.0.0

There are a few warnigs from migrate that have to be fixed. The toggles
in the Media Manager are also missing their proper icons.

Default only text string exists, via localized translation a wiki admin
can add his/her own (html) version.

mailwrap.html is back

@EMAILSIGNATURE@ added

Done:
Cleanup of the mail text signature.
The signature is deleted from the txt files and moved in to lang.php
Mailer.class.php updated to insert the signature

Fix:
- Cleaner text
- no more "-- "  "--" "---" "----" problems.
- mailwrap.html is not needed anymore an can be deleted (?)

Changed files in all languages:
lang.php
mailtext.txt
password.txt
registermail.txt
subscr_digest.txt
subscr_list.txt
subscr_single.txt
uploadmail.txt
pwconfirm.txt
showrev.txt

delete?:
mailwrap.html

This now pulls all data from official jQuery sources. Either their CDN
or their github account. Google tends to serve outdated or even broken
files :-(

Unfortunately there's no simple way to get the latest stable jQuery-UI
so for now the version has to be adjusted manually in the script.

This reverts commit 524df576.

Conflicts:
	inc/lang/bn/lang.php
	inc/lang/fr/lang.php

this has been done by a script and might not be 100% accurate

This was updated in the english translation a while ago, but was still
missing in some translations

When loading plugins, $lang might not be initialized yet, so use a
hardcoded error message instead, especially as this error should only be
displayed for the admin (and then fixed). This also removes the
previously localized message, it might be re-added as part of the new
extension manager.