Draft for libGDX Pay API.
Purchase object improved to accept both an integer or String in the constructor for the item identifier.
Merge branch 'master' of https://github.com/noblemaster/libgdx into iap
added gdx-pay to build
Merge branch 'master' of https://github.com/libgdx/libgdx
Merge branch 'iap' of https://github.com/libgdx/libgdx
Pay API:
 - removed PurchaseObserver - there is now only 1 single listener: PurchaseListener
 - itentifier changed to String (from int).
Merge branch 'iap' of https://github.com/libgdx/libgdx
Added payment processor stubs for Google Wallet/GWT and Stripe/Desktop.
Fix TextureUnpacker
add setCenterPosition and other methods to Actor
Merge pull request #2000 from jrenner/actor-centerpos

add setCenterPosition and other methods to Actor
Merge branch 'master' of https://github.com/libgdx/libgdx
Merge pull request #2002 from alex55i/unpackerfix

Fix TextureUnpacker
some scene2d ui docs
Merge pull request #2003 from jrenner/docs

some scene2d ui docs
Update Box2DBuild classpath.

Closes #2004
Added ObjectAL hack for fixing audio problems that happen sometimes.
Also use Foundation.NSLog for every Gdx log message.
Removed log spam of iOS preferences (no backend has log messages for this).
Fixes ShapeRenderer multicolor call to rect()

So, it seems that if you called rect() using all the parameters
(position, size, origin, rotation and 4 colors for the vertices),
if the ShapeRenderer was open on Filled mode, it actually ignored
any colors you gave it and render the rect on the current renderer
color (the one you set by calling setColor).

I fixed it by making the function use the colors you give it,
just like the other functions that take colors as parameters do.
Merge pull request #2009 from danirod/bugfix_shapecolors

Fixes ShapeRenderer multicolor call to rect()