Fix Mispositioned Tree Buttons in Firefox

Closes jpdevries/revolution#16
see screenshot, I still have no idea why an undefined class is being
added to the element twice
Fix issue where selecting search results did... nothing
Added IN output filter

Search inside comma delimited string. 

Example: [[*tv:IN=`blaat,test,value`:then=`Yes there is`:else=`No there isn't`]]
Fix loading of plugin events on Create Plugin screen
Fix tree button positions in Firefox

Merge remote-tracking branch 'origin/pr/699' into develop

* origin/pr/699:
  Fix Mispositioned Tree Buttons in Firefox
Fix issue where selecting search results did... nothing

Merge remote-tracking branch 'origin/pr/700' into develop

* origin/pr/700:
  Fix issue where selecting search results did... nothing
Add in/inarray conditional output filter

Merge remote-tracking branch 'origin/pr/702' into develop

* origin/pr/702:
  Added IN output filter
Fix loading of plugin events on Create Plugin screen

Merge remote-tracking branch 'origin/pr/704' into develop

* origin/pr/704:
  Fix loading of plugin events on Create Plugin screen
Support PHP use statements in Snippets and Plugins

This provides a more long-term solution for and closes #557