* Add different types for different mentions
* Remove redundant THREAD_ANY and THREAD_ROOT constants
* Make PostStore.Get return thread in order
* MM-17071 Add initial version of countMentionsFromPost
* MM-17071 Refactor comment mention counting
* MM-17071 Use mention counting when marking post as unread
* Fix shadowing in tests
* Remove repeated check of user count
* Refactor code using MentionType
* Update comments around -1 return value
* Move inner functions out of countMentionsFromPost
* Remove preconditions check as separate test case
* Update comments
* Add User.GetMentionKeys
* Revert "Make PostStore.Get return thread in order"
This reverts commit 22aa010cee359655fe75e1dc899cf0ffb0943c2a.
* Fix tests
* Fix merge conflict
* Add store.MentionAllPosts