* Add upgrade/downgrade pass for Add op.

* Add upgrade/downgrade pass for Divide op.

- Change default value of autobradcasting in v1 into NUMPY.

* Add v1 version for Equal operator.

* Rename helper functions to fix compiler errros.

Fix Divide op version.

* Add downgrade and upgrade passes for Equal op.

* Reformat test cases. Add helper functions.

Add UT for Equal op.

* Add upgrade/downgrade pass and UT for Greater op.

* Add upgrade/downgrade pass and UT for GreaterEq op.

* Add upgrade/downgrade pass and UT for Less op.

* Add upgrade/downgrade pass and UT for LessEq op.

* Add upgrade/downgrade pass and UT for Maximum op.

* Add upgrade/downgrade pass and UT for Minimum op.

* Add upgrade/downgrade pass and UT for Multiply op.

* Add upgrade/downgrade pass and UT for NotEqual op.

* Add upgrade/downgrade pass and UT for Power op.

* Force ops version 1.

* Don't inline templates.

* Fix namespaces and some formatting.

* Update ONNX Importer to produce v1 nGraph nodes.

* Fix function return type.

* Fix uninitialized local variable warning.

* Fix confilicting declarations.

* Apply clang-format.

* Fix errors for distributed nGraph with unavailable classes.

* Fix downgrade pass for LessEqual op.