use gradle config cache

Author: CampelloManuel

gradle.properties

@@ -23,3 +23,6 @@ org.gradle.warning.mode=all
 # until we remove AndroidAnnotations, classes like ActivityMain still need
 # @EActivity(R.layout.activity_main), therefore resource Ids must be final
 android.nonFinalResIds=false
+
+# for faster builds
+org.gradle.configuration-cache=true