Update libGDX pom's.

Update libGDX version from 0.9.9-SNAPSHOT to 1.0-SNAPSHOT in
nifty-examples-libgdx and nifty-renderer-libgdx pom's. Add helpful
comments to the desktop and android pom's in nifty-examples-libgdx.
Clean up formatting of nifty-examples-libgdx and nifty-renderer-libgdx
pom's.