IVGCVSW-3418 Add Arm NN front end support for the new Stack layer

 * Added new StackLayer class
 * Made necessary changes to Descriptors, ILayerSupport, ILayerVisitor, etc.
 * Added unit tests

Signed-off-by: Matthew Jackson <matthew.jackson@arm.com>
Change-Id: Ieb97a928a342ffe1901c6058eb895711c358fd3d
diff --git a/Android.mk b/Android.mk
index e2daeea..b9cc6e5 100644
--- a/Android.mk
+++ b/Android.mk
@@ -132,6 +132,7 @@
         src/armnn/layers/SpaceToDepthLayer.cpp \
         src/armnn/layers/SoftmaxLayer.cpp \
         src/armnn/layers/SplitterLayer.cpp \
+        src/armnn/layers/StackLayer.cpp \
         src/armnn/layers/StridedSliceLayer.cpp \
         src/armnn/layers/SubtractionLayer.cpp \
         src/armnn/layers/SwitchLayer.cpp \