Allow building of an OEM friendly TWRP

Disable theming
Disable creating the TWRP folder for the settings file
Change factory reset on data/media devices to a full wipe

Change-Id: I3104282b5dd3f55dfff7c8cf39c72750af08563d
diff --git a/gui/Android.mk b/gui/Android.mk
index 40b67d8..19bb0bc 100644
--- a/gui/Android.mk
+++ b/gui/Android.mk
@@ -68,6 +68,9 @@
 ifeq ($(HAVE_SELINUX), true)
 LOCAL_CFLAGS += -DHAVE_SELINUX
 endif
+ifeq ($(TW_OEM_BUILD),true)
+    LOCAL_CFLAGS += -DTW_OEM_BUILD
+endif
 
 ifeq ($(DEVICE_RESOLUTION),)
 $(warning ********************************************************************************)