#884 No horizontal scrollbar in [code]
Merge pull request #89, fixing #884.

Conflicts:
	style/Air.css
	style/Earth.css
	style/Fire.css
#887: Fix invalid callbacks for forum, topic, post, and user BBCodes.
#895: Fix URL-unfriendly characters in random keys with readable option.
#891: Remove unused line of code in generate_quickjump_cache.
#822: Move include line to the random_key function
#905: Merging topics hangs when users are subscribed in Postgres and SQLite. Thanks Storlek.
#908: Move users info cache regeneration before sending emails in register.php. Thanks Visman.
#710: Change $smtp_host to $local_host for HELO and cache $local_host. Thanks yoorick.
#884 Fix code field scroll bars
#896 Fix all 404 Not Found errors
#896 Fix all 403 Forbidden errors
#911 Fix borders in Internet Explorer 11
Merge pull request #91 from Studio384/master

#884 Fix scrollbars, #896 HTTP 403/404 errors and #911 SCC bugs in IE11