GitHub #292 Move BackendRegistry.hpp to the public API

 * Moved to BackendRegistry.hpp include/armnn
 * Updated makefiles and sources accordingly

Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>
Change-Id: I4d83abb581d523218a880c879fcf30c9611f7fd7
diff --git a/Android.mk b/Android.mk
index c91b43f..dbc999e 100644
--- a/Android.mk
+++ b/Android.mk
@@ -78,6 +78,7 @@
 LOCAL_SRC_FILES := \
         $(ARMNN_BACKEND_SOURCES) \
         src/armnn/BackendHelper.cpp \
+        src/armnn/BackendRegistry.cpp \
         src/armnn/Descriptors.cpp \
         src/armnn/Exceptions.cpp \
         src/armnn/Graph.cpp \