updated versions in DependencyBank
[maven-release-plugin] prepare release 1.3.1
[maven-release-plugin] prepare for next development iteration
updated CHANGES
increased Version
add getRegion to PolygonSprite
Javadoc

Closes #2236
Add ability to set a tile's texture region
Merge pull request #5 from libgdx/master

merge with libgdx/libgdx