Update for GdxPay (does not compile!).
Update for offer to allow chaining.
Further updates to IAP/PurchaseManager.
Fixed ButtonGroup not removing from the checked buttons list.
Keep names for drawables to make debugging easier.
Make Button use padding of all drawables, not just the first.

#2322
Merge remote-tracking branch 'origin/master'
Have Button update background in setStyle.

closes #2322
Fixed copying TintedDrawable.
Chachachachanges
SelectBox, configurable show and hide actions.
Add isCatchBackKey to Input interface
Minor IAP updates/changes (does NOT compile!).
Added getLevel and getIndentationSpacing.
Javadocs.
Merge remote-tracking branch 'origin/master'
Javadocs.

#2326
Bugfix for Viewport.getPickRay
Merge pull request #2327 from nooone/viewportpickray

Bugfix for Viewport.getPickRay
IAP System: new tests working over OpenIAB :-D