Previously the rmdir could be executed when the lock directory had been
deleted by another indexer already. This could lead to a race condition
when another indexer call creates the lock again between the if and the
rmdir. This issue still exists for stale lock directories but they
normally shouldn't exist.
This also prevents the loop from becoming an endless loop when the lock
directory can't be created.
This change also fixes a syntax error in the indexer and prevents an
endless loop when the lock directory exists but can't be deleted.

Changes:
  * XML-RPC now correctly allows leading and trailing _
  * Error messages from XML-RPC are correct
  * MEDIA_UPLOAD_FINISH has a sixth param specifying the move function
  * Not having upload rights when using media_upload throws a msg

This patch makes the plugin manager not descend into symbolically linked
directories as this behaviour is not expected from a recursive delete.

Functionality changes:
  * deleteAttachment now triggers MEDIA_DELETE_FILE (closes FS#1568)
  * deletion success msg in mediamanager is correct, even when the ns dir
    was deleted
  * media_delete changed quite a bit

I also adjusted the coding style to match our other JS classes

When a <select> tag has the class "quickselect", this script will
automatically submit its parent form when the select value changes.
It also hides the submit button of the form.

For locks and getRevisions there hasn't been any acl check. In many
other cases the id hadn't been cleaned before the acl check was done
which means that many acl rules that should be applied weren't applied.
So e.g. when you have read permissions for the root namespace but not
for a subnamespace you could add a leading ":" and the permissions for
the root namespace will be used instead of the permissions for the
subnamespace. This did not apply to writing pages and reading media
files, but writing and deleting media files have been concerned as well
as reading both plain and html versions of pages.

This only concerns installations where XML-RPC is enabled (default is
disabled) and XML-RPC is allowed for all or untrusted users.

This makes it possible for plugin and template authors to overwrite or
extend the quicksearch JavaScript logic.

This patch moves the shortening of namespaces in the quicksearch results
to JavaScript. This makes it independend from used template and will
always try to fill the width of the result pane correctly.

Things missing:

  * Make it work with RTL-languages
  * Check Browser compatibility (only tested in Chrome so far)