Use $mybb->version instead of $mybb->version_code

This both more consistent and friendlier.
Execute queries on the master database if the last write query was to the master

This is a port of the work by @ImadJomaa which never reached the 1.6 series.

Internal thread: http://community.mybb.com/thread-119212.html

As I understand it, there were a few incorrect comments about which database was being written to (master/slave) and the query() method would always query the slave. If the last query was a write query to the master, the next query should be to the master too due to latency with slaves being updated.
Remove anchor from custom profile field title

The description is shown below the title so there's no need to show it on hover.
Improve draggable fields consistency
Fix typo
Fix typo