FS#2700)

Note: These changes don't work yet. The cookie is not set and deletes the old
one.

This should make migrating from MediaWiki a bit easier.

Indexer: Added page and meta value rename functions

* subscription: (25 commits)
  link directly to subscription management in mails
  only use mailfromnobody for bulk mails
  added missing context for list mails
  readded mailfromnobody to subscription sending
  correctly escape diffs in HTML mails
  fixed lists in HTML mails
  simplified subscription->add() code a bit
  comment adjusted
  removed unused vars
  removed data parameter in subscription_handle_post()
  fixed tests
  some reformatting
  added compatibility function
  moved registration notification to subscription class
  fixed merge error in inc/auth.php
  consolidate more notification code in subscription class
  minor cleanup
  initialize new subscriptions with current time
  fixed subscription management
  correctly check if subscriptions are enabled
  ...

The new deletePageNoLock method is used by renamePage and avoids that
the index needs to be unlocked and locked again for deleting the page.

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

Custom editors can also be loaded when not a section is given. For
example this happens on a preview click where the page is already
separated into pre, suf and text.

This reverts commit f2cb3ec7.

Turns out I was too fast merging this. I can't get PHP's bzip handler to
handle a bzip1 compressed file.

handle bz (bzip not bzip2) better

fixes from bee9f377 commit notes

in fact .tbz is tar.bz (bzip1) and .tbz2 is what tar.bz2 is used
commonly.

Added unit tests

Hurray, tests pass!

Currently both the 2nd and the third assertions fail
(the first one is just for upcoming non-regression)

wiki.getAttachments returns 'perms' according to documentation

Because wiki.getAttachments now returns 'perms' instead of 'perm'

Check search limit depth with an inequality

Don't remove page version from result if uneeded

With these functions that search index can be updated after page moves
or mass metadata updates without the need to reindex the whole
page/wiki. These functions will be used by the new pagemove plugin.