API Changes

Added two new methods to the HUDItem base class, neither of them are
abstract so you shouldn't need to make any changes to existing
extensions of the API. HUDRegistry gets an updateCounter variable.
RenderAssist gets two new helper methods, drawRect and
renderInventorySlot
Add chat drawing

Should be compatible with mods that add custom chat things. (IE
tabbychat)
Version Revision
Maybe.
Update Vanilla HUDItems to 1.6.4