[Browse] Splitting up Menu Gesture

Splitting up the context menu gesture's functionality into
separate context menu gesture and context menu actions.
The gesture watches for right-clicks, while the action
displays the menu. #33.

platform/commonUI/browse/res/templates/menu-arrow.html

@@ -22,5 +22,5 @@
 
 <span ng-controller="MenuArrowController as menuArrow">
     <a class='ui-symbol context-available'
-       ng-click='menuArrow.contextMenu()'>v</a>
+       ng-click='menuArrow.showMenu($event)'>v</a>
 </span>