Threadmarks Pro 2.21.1

• Fix off-by-1 error resulting in threadmark list of 2 not displaying both items

• Fix how a thread's threadmark list would not show all categories of threadmarks for some users.
• Fix that 'recent threadmarks' sort order was not stable from thread-to-thread
• Minor installer cleanup

• XF2.1 compatibility fix for RSS support
• Improve upgrading from free version of XF1 Threadmarks

• Fix cases where the content user's name is displayed instead of the threadmark creator's name
• Respect "View threadmarks" permission when offering to add threadmarks

• Compatibility fix when extending javascript

• Do not push deleted/moderated threadmarks into search index
• Ensure Threadmark label is indexed for the first post of a thread
• Fix inline created threadmarks are not spamchecked

• Ensure Threadmark index spam checking occurs on thread creation as required
• Do spam-checking of Threadmarks on create/edit as required

• Fix typo breaking XF1 => XF2 upgrade process

• Improve upgrading from old XF1 (v1.3.x) versions of threadmarks

• Fix "Cannot call method getRedirectLinkForThreadmark on a non-object (NULL)" on viewing a threadmark with hard deleted content.