remove TRANSFORM_OT_snap_type, use WM_OT_context_menu_enum instead.
add Ctrl+Shift+Tab shortcut for selecting snap type to the UV editor too.

also added icon drawing to WM_OT_context_menu_enum() so it gets the icons from the enum to draw them in the menu.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@53773 954f8c5b-7b00-dc11-b283-0030488c597c