Adding first pass of Android keyboard

Known issues: only onInput callback works, need to make return work
Android keyboard cleanup and tweaks

Added Return callback for when the user clicks 'done' on the keyboard.
Merge pull request #642 from moai/feature/android_keyboard

Feature/android keyboard
Clarify description of textbox color escapes, fixing one typo and
reducing confusion between number of bits and number of values represented.
Merge pull request #643 from seebs/seebs

Clarify description of textbox color escapes
first phase of offscreen rendering architecture completed
a few more minor cleanups to layer rendering
added setClearColor () to MOAILayer; added samples to test multiple viewports and multiple viewports inside an offscreen buffer
Merge branch 'integration' of github.com:moai/moai-dev into integration