* IntelGPU backend. Use common nGraph optimization passes

* PR1667. Move variable definition.

* Add CPU horizontal fusion pass for inception.

* Name change.

* Move horizontal fusion to cpu_fusion.

* Change horizontal fusion pass for inception to a general horizontal fusion pass.
Add a unit test conv_horizontal_fusion to cpu_fusion.

* Rename files.

* Correct cpu_fusion.hpp.

* Add NGRAPH_DEBUG.

* Set native layout when input format of slice is nChw16c or nChw8c and lower bound of
channels is not a multiple of 16 or 8.

* added stream writers to dump meta information related to CONSTANT, INTERMEDIATE, PARAMETER's

* WIP added method to dump Input and output reference address in to debug manifest from cpu_call_frame

* added suppport to dump memory refernce in the debug manifest

* - added macro to dump debug manifest
- added support to release_function once dumping the memory references

* added a method to write a generated stream to a file

* dont release function, if NGRAPH_DEX_DEBUG flag set

* Addressed PR comments
-   dump debug manifest using stringstream instead of CodeWriter
-   Moved dumping debug manifest logic to cpu_external_function

* revert changes to call_frame

* - Addressed PR comments

* :Remove call_once from dumping debug_manifest

* address PR comments

* address PR comments

* extend concat elimination to fold slice + reshape

* relax branch tip to be anything not just goe

* add support for transpose when concat of slice + reshape occurred on internal axis.

* simplify reshape order permutation

* multi-axis slice + concat do not cancel and are now disabled. generalize detection of axis reordering when intermediate reshape is present
to include logical reshape and reshape that results in axis reordering for the cases: parent_shape.size gt, eq, and lt concat_shape.size.

* check that slices are in order

* add one user check on reshape

* add more checks

* fix warnings

* Reshape axis order did not include enough dimensions when the transposed and reshaped result was of lower rank.

* inject details into visualize_tree pass

* address bob's feedback

* revert back to map

* - fixed performance_counter for CPU DEX

* made changes to start clock @ the first functor and collected perf_counter @ the exceution of last functor for given kernel execution

* - made changes to have max_pool kernel to have exactly one functor
- assert if functor != num_of_ops

* fixed profiler_counter for TBB execution

* avoid unnecessary calculation to enables<map> value

* Addressed PR comments
-   updated "enables" -> list<functors>

* Common pass registration for codegen and Dex

* Make return indices optional for cpu workspace insertion

* [ONNX] LRN op

* Review fix pt. 1

* Unsqueeze Fix

* Pooling fix

* set global line ending options for repo

* Normalize line endings

* add newline at eof

* IntelGPU backend. Compile function moved to use switch for operations.

* PR1626. IntelGPU backend. Test unhandled_op fixed.

* PR1626. Comments addressed

* Fix output element type for selection functions

* style

* Use MKLDNN for non-strided slice ops.

* Remove unused variables.

* Add utility function is_strided to graph_util.
Add datatype check for slice in cpu_assignment.

* Create blocked mkldnn memory desc for output when input format is blocked.

* Add slice converLayout fusion to cpu_post_layout_optimizations.

* Rename tensor_view.
Fix a bug.

* Rename a variable.

* Use the Eigen OpenMP thread pool device

* CMake: Work around ancient non-compliant compilers used by the CI system

* Work around the broken CI system by making OpenMP optional

* Add support for Quantized Convolution op via mkldnn for IA backend (codegen + DEX)

* Use call_with_validate

* Style fix

* Fix clang compile errors

* fix Sphinx version for Jenkins and update nG versioning

* Try stable verison of Sphinx 1.7 instead

* postpone adding dropout op to make CI building happy

* sort op list

* use op_tbl

* throw unsupported_op exception when appropriate

* remove dead code

* Add more use of NGRAPH_OP macro to remove boilerplate definitions/implementations

* revert moving class out of namespace

* change from switch to dispatcher map

* [ONNX] Squeeze op

* Review fix pt. 1

* Type change

* [ONNX] Transpose op

* Review fix pt. 1

* Review fix pt. 2

* [ONNX] Slice op

* Review fix pt. 1

* Review fix pt. 2

[ONNX CI] nGraph-ONNX CI Hotfix

* refactor distributed code

* add test file changes

* add distributed class

* update test file