IVGCVSW-4439: Adding Elu support to Activation

 * Added CpuRef implementation
 * Added Unit Tests
 * Added Quantizer Test
 * Enabled Tests for Neon and CL backends on fp32 only
 * Added to Serializer

Signed-off-by: David Monahan <david.monahan@arm.com>
Change-Id: Ic23e1797dbc9352b40678c389d7fe2b836b582ea
diff --git a/src/armnnDeserializer/Deserializer.cpp b/src/armnnDeserializer/Deserializer.cpp
index 3bbd71a..61a38f9 100644
--- a/src/armnnDeserializer/Deserializer.cpp
+++ b/src/armnnDeserializer/Deserializer.cpp
@@ -421,6 +421,8 @@
             return armnn::ActivationFunction::Sqrt;
         case armnnSerializer::ActivationFunction_Square:
             return armnn::ActivationFunction::Square;
+        case armnnSerializer::ActivationFunction_Elu:
+            return armnn::ActivationFunction::Elu;
         default:
             return armnn::ActivationFunction::Sigmoid;
     }