[BUG #6865] Removed some deprecated code.
[BUG #6865] Removed qx.bom.Collection (deprecated)
[BUG #6865] Removed qx.fx (deprecated)
[BUG #6865] Removed old virtual list (deprecated & experimental)
[BUG #6865] Removed deprecated lang features.
[BUG #6865] Removed deprecated CSS features.
[BUG #6865] Removed deprecated events mixin.
[BUG #6865] Removed deprecated mobile code.
[BUG #6865] Removed #use hint to already removed deprecated class.
[BUG #6865] Removed deprecated method in the HTML area.
[BUG #6865] Removed deprecated comment.