[Py] Change Python version for tox

* CPU: Fuse zero-padded convolution backprop filters

* CPU: Add a testcase for zero-padded convolution backprop filters fusion

* initial support for recurring matching

* fix a bug where patterns weren't populated w/ matched nodes; add recurrent tests

* add a missing newline

* address feedback

* fix function comment

* Add/update Python wrappers for nGraph operations.

- NotEqual, OneHot, Power, Sqrt, Relu, Sign, Sin, Sinh, Tan, Subtract, Select, Tanh, Sum, Reduce,
Softmax, ReplaceSlice, Reverse
- Add UT for Relu, Sign, Sin, Sinh, Sqrt, Tan, Tanh,

* Add UT for cases when Cos and Sin are giving incorrect results.

* Alphabetically sorted imports.

* Small refactoring.

- Update docstrings
- Remove unnecesary auxiliary local variable.

* make Input descriptors node owners

* rename src_node to m_src_node

* Update README to make it consistent with ngraph-neon

* Add instruction to clone pybind in README

* Address feedback on README

* visualization tracing

* visualize -> m_visualize. add a programmatic way to enable visualization. tweak pass names

- Enable Padding op
- Supress multiline comment warning
- improve tox configuration

* enable TensorView to use pre-allocated mem

* proper check for nullptr

* add unittest for custom mem with tensorview and feedback

* minor fix from feedback

* support GPU TensorView custom mem

* feedback fix and code format

* CPU: Optimize Sum reductions

* CPU: Optimize 1D reduce all case

* CPU: Optimize 4D reduce all sum

* CPU: Tweaks

* Formatting fixes

* Enable Travis CI

* Enable Travis CI - update README

* Travis CI - Parallel testing

* saved a simplified contrib/docker/Makefile and helper scripts

* fixed flow for make targets

* restored original definition for setting the PARALLEL option on the command line per github comments

* remove double build for make install targets

* added a save for the ngraph_dist_gcc.tgz to maintain existing behavior

* fixed passing the PARALLEL value to the make targets

* integrated latest working build-ngraph-and-test script

* integrated the latest working Makefile

* removed reference to the THIRD_PARTY_CACHE_DIR (for future)

* updated the contrib/docker/README.md file

* refactor Adjoints to support multi-output ops

* passing tests

* switch to generate_adjoints(deltas) and backprop_node

* remove debugging code

* fix error msg

* fix typo adjoitns

* fix comp errors in mnist_mlp

* [Py]Fix problem with double set layout

* Extend UT for coverage double set layout

* add layouts and users check
* add convrelu handler

* Fix clang warnings on macos

* Conditionalize warning on Apple clang version.

* More extensive examples of graph building.

* Review comments

* Review comments

* Review comments

* WIP support bn training for global_stats

(cherry picked from commit eb81a37328ea177b1d58c9eebdbb345e0fa25f0d)

* - Style fix
- Fix test case

* Addressed PR comments
- added support for bn training/inference with a same ctor
- added more verbose comments in bn header

* Fixed bn serializer and default value in bn ctor for bwd compatibility

* proposed docs change

* - Addressed PR comments
  - added support to compute bn inference/training using same mkldnn kernel with global stats

* fix unit bn relu unit test

* add random init for all input types, not just float

* remove debug

* initial refactoring using PM

* unit test pass

* cosmetic changes

* add another rnn test

* address louis' feedback

* lower-case labels

* 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.

* Change serialize routine

* Change serialize routine call for onnx

* Update function type annotation.