IVGCVSW-6382 Add Gather operator support to ONNX parser

 * Add ParseGather to support Gather operator on ONNX
 * Add Support of int64 converted to int32 for constant
 * Add OnnxParserTestUtils
 * Refactor ValidateTensorShapesFromInputs of GatherLayer
 * Unit tests

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: Ie9dff640240e14a062fef38f7faf0ccc212de5f7
diff --git a/docs/01_01_parsers.dox b/docs/01_01_parsers.dox
index 97497fe..31b7687 100644
--- a/docs/01_01_parsers.dox
+++ b/docs/01_01_parsers.dox
@@ -49,6 +49,9 @@
 - Flatten
   - See the ONNX [Flatten documentation](https://github.com/onnx/onnx/blob/master/docs/Operators.md#Flatten) for more information.
 
+- Gather
+  - See the ONNX [Gather documentation](https://github.com/onnx/onnx/blob/master/docs/Operators.md#Gather) for more information.
+
 - GlobalAveragePool
   - See the ONNX [GlobalAveragePool documentation](https://github.com/onnx/onnx/blob/master/docs/Operators.md#GlobalAveragePool) for more information.
 
@@ -64,6 +67,9 @@
 - Reshape
   - See the ONNX [Reshape documentation](https://github.com/onnx/onnx/blob/master/docs/Operators.md#Reshape) for more information.
 
+- Shape
+  - See the ONNX [Shape documentation](https://github.com/onnx/onnx/blob/master/docs/Operators.md#Shape) for more information.
+
 - Sigmoid
   - See the ONNX [Sigmoid documentation](https://github.com/onnx/onnx/blob/master/docs/Operators.md#Sigmoid) for more information.