CastMount

First official release!

The API has been overhauled several times to improve efficiency and stability.
It will surely change again as I develop towards 2.0.

I will probably document the API as I decide on what is a keeper and what is a waste of lua.

**** Known Caveats ****

Please let me know of any unexpected behavior!

All known taint issues with the CastMount Button have been resolved.
Please report any taint caused by combat encounters and describe what you were doing when you received the error.

**NOTE** the Configure Menu has not been tested in combat yet and will most likely cause issues. Seeing as configuring this addon in combat is not really necessary, the window will almost certainly be hidden during combat and restored afterwards in a future release.

Known Bugs:

 * When learning a new mount companion, the intended behavior is to make it the current selected mount by the CastMount Button.  This does not happen properly and the mount is not even noticed by the UI until it is reloaded or World of Warcraft is restarted.  The fix is already in the works for the next release.