increase the java heap to 512M when running proguard. Otherwise the Shem build runs out of memory
building the Utopia jar file.

Change-Id: Id3491f1f8f1640aa532c5ec30353d26a8d7ff8ac
Merge tag 'android-4.3_r2.1' into jellybean-mr2.1

Android 4.3 release 2.1