Added OnElementNotFound system event
CSS Twerks

Un-uglifying the required/invalid input state (now uses red border and
font awesome icon)
Adjusting x-panel table header hue (to $darkNeutral)
removing legacy green buttons in package manager (now $primary)
retina-tizing x-btn-split (Download Extras button)
uberbar result hovers (%nav-item)
Help Page Improvements

Retina CSS MODX Help Logo
Primary Action styling on sign up button
Fix error with package management caused by #691
Add preg_quote to friendly_alias_word_delimiters characters

This allows you to add / as a friendly_alias_word_delimiter without breaking the regex
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
Implement auto-saving on Content Types grid
Fix broken processor actions on Import screens
Fix autosave grid action for media sources, remove unneeded autosave parameter on types grid
Support PHP use statements in Snippets and Plugins

This provides a more long-term solution for and closes #557
Implement auto-save on Content Types grid

Merge remote-tracking branch 'origin/pr/705' into develop

* origin/pr/705:
  Implement auto-saving on Content Types grid
Fix broken processor actions on Import screens

Merge remote-tracking branch 'origin/pr/707' into develop

* origin/pr/707:
  Fix broken processor actions on Import screens
Fix autosave grid action for media sources

Merge remote-tracking branch 'origin/pr/708' into develop

* origin/pr/708:
  Fix autosave grid action for media sources, remove unneeded autosave parameter on types grid
Fixes Tree Context Refresh Positioning Bug
Removing Duplicate Sass Declarations
Adding Primary Button Styles