Fixing #597 and cleaning up admin/inc/functions_themes.php in terms of docblocks and variable/array initialising.
Re-caching stylesheets on upgrade for 1.8 to ensure existing stylesheets get minified.
Use jquery.sceditor.mybb.css from plugin sceditor for Mybb.
Merge branch 'feature' of https://github.com/mybb/mybb into fix-597

Conflicts:
	install/resources/upgrade30.php
Added task to re-cache stylesheets via ACP without having to manually go into each style and save it.
Fixes 2nd issue in #526 - No content on draft

#526
Merge pull request #795 from PirataNervo/featurefix-526

Fixes 2nd issue in #526 - No content on draft
Feature #493 Invite-only joinable groups
Fixed bug with join requests in Admin CP
Working on #756 Remove Hardcoded HTML
Missed two bits in usercp.php
Fixes #526 correcting PR for 2nd problem
Working on #454 Hide stuff users don't have permission to use
Hide "Contact Us" link if diabled to guests or disabled altogether.
Working on #756 Remove Hardcoded HTML
Put code in wrong place >_<
Fixes Incorrect dateline on preview of post/thread of unregistered user, refs #465

* editpost.php
  * added dateline to post select query, when updating a guest's post
Merge pull request #785 from euantorano/fix-597

Fixing #597 and cleaning up admin/inc/functions_themes.php in terms of d...
Merge pull request #797 from Nik101010/fix-465-feature

Fix #465
Merge pull request #672 from martec/scmybbcss-2

Use jquery.sceditor.mybb.css from plugin sceditor for Mybb.