Fixes #2212 Drafts update the forum last post

http://dev.mybb.com/issues/2212
Fixes #2162 Threadlist can contain a thread without name, id etc.
Minor fix
Update readme.md
add mass mail languages
Fix #289 Pop up smiley inserter doesn't use cursor CSS
Fix #370 Admin Permissions breadcrumb does not display username if user is an admin through an additional group
Fix #370 Add SQLite/PgSQL database queries
Fix #258 Stick Thread checkbox is not checked by default
Fix #379 User(s) browsing this thread incorrect when linking to post
Fix #381 dbpdoEngine::num_rows() doesn't work as expected
Minor formatting
Fix #281 [Theme] Creating new theme using admin panel
Fix #295 Search & replace in admin panel
Fix #317 User Merge bug/problem
Fix #282 [Plugins] Akismet 1.2.1 installation error
Make sure users aren't on their own buddy/ignore lists
Build a new array instead of modifying $stylesheet
Call array_diff() before implode()

I missed that.
trim() imploded lists

This _should_ work as we can never have a comma at the beginning or end...