Revert "Change AndroidTarget to subclass JvmTarget"

This reverts commit ba0bf9ff1f0b87c4334c480259cc6a0edf5dd143.
Revert "Add JarDep to aaptGen create_target method"

This reverts commit 097e3a099bd90d5c29e1cc9ed33bcf39cb737450.
Add JarDep to aaptGen create_target method

This is two commits, one by me and another patch from jsirois.

This adds the android.jar to the created target and allows
the android target to properly compile. This outputs
java class files.

The java compile requires a java target. This also
finishes adding the android.jar. AndroidTargets will
now compile through pants. ivy requires a rev to resolve
jars and that fits so we can process each sdk group
together.

Reviewed at https://rbcommons.com/s/twitter/r/822/