beginning topic searching + new hook
Merge branch 'master' into topic_searching
Merge master
Merge branch 'master' of https://github.com/NodeBB/NodeBB

Conflicts:
	src/groups.js
optimize ACP groups screen, jQuery caching
Merge branch 'master' of https://github.com/NodeBB/NodeBB
revert package.json
Merge branch 'master' of https://github.com/NodeBB/NodeBB
fix upgrade.js according to CodeClimate recommendation, remove BOM
closes #1941
closes #1970
Merge remote-tracking branch 'origin/master' into 0.5.1
Merge remote-tracking branch 'origin/master' into 0.5.1
Merge remote-tracking branch 'origin/master' into 0.5.1
closes #1976
show user names who upvoted a post on mouse over
Merge remote-tracking branch 'origin/master' into 0.5.1
Merge remote-tracking branch 'origin/master' into 0.5.1
callback
closes #1974