Restructure the folders to include the Robolectric plugin.

Change-Id: I419ea4077af4bd6735901479e766dc46d2423f0e
Using Gradle's build jniLibs folder to include the SO files.
Issue #342

Change-Id: I25bf37a7a3d583d69f5e8bf493b76dc8fc0a9cf1
fix for issue #339

Change-Id: I30ba0d529916894644a7371074d75f9203e68e76