* enable parameter validation for all unit tests

* remove deprecated

* remove all legacy Backend API usage

remove deprecated files

* pull in changes from master

* fix GPU calls

* disable tests in convolution generator

* update per PR comments. Enable performance counter feature.

* update per PR comments

* fix build error

* fix conditionally compiled test :(

Adjust CallFrame argument order to match Function

* Replace using aliases with actual classes

- enable distributed ngraph (MPI)
- add AllReduce op to ngraph core, interpreter and CPU backend
- add AllReduce unit test