Implements "soft" post merging which leaves the source post alone
This requires support for each add-on, supports
Vote Tally
Dice roller
Threadmarks
Sticky any post
Adds permission for:
Moving thread
Viewing thread moderator logs
Merging thread
Soft merging post
Hard merging post
Fixes a number of scaling issues with inline mod tools related to locking when updating threads after moving/copying posts
