* quick fix to add openmpi as default

* add finalize to distributed class & use unit test

* use intel mlsl github link

* apply style

* address a few comments

* fix test

* update nbench cmake

* remove extras

* fix a bug

* add counter to finalize and cleanup

* test ci error

* address mlsl ci error

* update flag names, as mentioned in pr comment

* revert back the link to mlsl repo and tag

* add flag to finalize

* apply style

* debug with info

* delete when flag is true

* add distributed setup class works, tests pass

* fix style

* remove extra instance

* disable the test due to a bug

* change flag to ompi

* remove the dependency of setting NGRAPH_DISTRIBUTED_ENABLE flag

* cleanup

* change extern to static

* remove the option NGRAPH_DISTRIBUTED_ENABLE setting this flag

* formatting

* update flags not catched by ci

* make unique pointer

* remove unused bool, fix clang error

* update licenses for 2019

* style

* make validate public

* move compile call outside of call for unit tests

* fix compile error

* one more error

* change compile call to return Handle

* make CPU require compile() before call()

* fix unit tests to call compile() before call()

* fix failing ops

* update unit test

* revert some changes

* more fixups

* more diff cleanup

* a few more issues addressed

* more fixes

* update API

* more updates

* fix test_ops.py

* fix

* another attempt to fix

* fix unit test

* fix test error

* Move ParameterVector and ResultVector to the ngraph namespace where they belong

* update python wrapper

* more python fixes

* style

* Update setup.py

* fix some new code

* move backend specific test files to test/backend directory

* remove unit_test_control

* move tests back to test root

* fix comment

* wip

* fix manifest

* refactor distributed code

* add test file changes

* add distributed class

* update test file

* use line comments instead of multiline comments for license header

* update more

* update new files

* more header updates

* style

* 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