Removed the ATTR_A_COL attribute and replaced it with ATTR_OPACITY.  Alpha and alpha-multiplied color channels are no longer exposed to Lua; only opacity and the unmultiplied channels, as in Cocos2D.  Removed seekColor and moveColor because they would break, and they're silly anyway.  ADD_COLOR, INHERIT_COLOR, and COLOR_TRAIT might also be broken, but I have no idea how they work.  Lulz.
Removed lines I commented out.
Merge pull request #19 from mindsnacks/feature/cocos-style-opacity

[Final] MOAIColor - Replacing alpha with opacity