* - templatize computing binary elementwise
- added lowering support for Add, Sub, Multiply, Divide

* - Added Support for Greater and less Op

* -Add support for Minimum and Maximum

* use edsc::intrinsics::select instead of terenary operator

* Addressed PR comments

* - return after the conditional check

Fix a mismatch after changing get_inputs API.

* Initial sub-graph extraction

* Works without detaching input edges from sub-graph

* Added removing input edges to graph

* Works with whole func sub-graphs. Inputs edges to sub-graph are still there

* Works on 2 exclusive sub-graphs. Still not on merged sub-graphs

* Revert removing inputs to sub-graph. nGraph validation crashes

* Added 3 sub-graph test. Remove compiled_kernel fusion pass. Comments

* Revert some changes

* Added cycle detection. Removed unit-tests to backend_mlir.in.cpp. Still not fully functional

* Construct CK nodes after finding outputs to preserve the graph.

* Fix topological sort. UTs pass.

* Minor fixes

* PR fixes

* Enable mlir tests only when building with MLIR on

* Support MLIR lowering of Relu

* Use EDSC comparison

* style-apply

* Use .inc file for Conversion classes list

* Disable i32 Relu for plaidml