remove docs/TODO: see issues marked as "feature".

https://github.com/kanaka/noVNC/issues?labels=feature

docs/TODO

-- Use requestAnimationFrame for frameBufferUpdate polling
-
-- Use WebSocket binary API when available.
-
-- Scaling support
-
----
-
-- IE 9 improvements.
-    - https://github.com/gimite/web-socket-js/issues#issue/41
-    - try window.atob instead of decode for better performance
-
-- Keyboard menu/panel:
-    - Move CtrlAltDel button here
-    - direct text entry with Send/Paste button
-    - Ctrl Once/Lock, Alt Once/Lock, SysRq Once/Lock
-    - Highlight menu icon when keys are locked
-
-- zlib/tight support (even if slow)