Version bump to 0.6.4-SNAPSHOT
ddmlib version now r16, up from r10
sbt version now 12.2, up from 12.0
Don't strip R.class from referenced libraries

This is needed when referencing 'android' libraries that contain
resource definitions (such as the google play services library).
Does anyone know why these were previously being stripped?
Added keys for proguard custom '-injars' parameter and custom filtering in jar files from '-injars' parameter.
Fix typo in apklibPackageTask
Select appropriate signing algorithms on JDK 7.

On JDK 7, default signing methods are incompatible with android.
So signed by default APKs won't install. This fixes it.