* Add python wrappers for nGraph Cos, Cosh operations.

- Update docstrings.

* Enable auxiliary function running computation to accept multiple input nodes.

* Python wrapper for nGraph Dot function with UT.

* Update python wrappers for nGraph Exp and Equal operations.

- Update docstrings.
- Add UT for exp.

* Update python wrappers for nGraph Floor, Greater, GreaterEq, Less, LessEq operations.

- Update docstrings.
- Add UT for ng.floor.

* Update python wrapper for nGraph Log operation.

- Update docstring.
- Add UT.