Faster plugin updating from UI control

Send a broadcast back and forth to speed up the rate at which plugins
are enabled or disabled.

Also update make files to handle exclude tests better.

Test: Manual
Change-Id: Ic8f45c663c3a5e5fd4b3e9e2f79480e155845c14
diff --git a/packages/SystemUI/Android.mk b/packages/SystemUI/Android.mk
index ffddf02..d1e1060 100644
--- a/packages/SystemUI/Android.mk
+++ b/packages/SystemUI/Android.mk
@@ -54,6 +54,4 @@
 
 include $(BUILD_PACKAGE)
 
-ifeq ($(EXCLUDE_SYSTEMUI_TESTS),)
-    include $(call all-makefiles-under,$(LOCAL_PATH))
-endif
+include $(call all-makefiles-under,$(LOCAL_PATH))