Modify Gather constant folding to support v1 op.

* WIP

* WIP

* WIP

* WIP

* style

* WIP

* WIP

* Add err msg

* Fix headers and cleanup

* Fix MLIR build on mac OS

* Style

* Style

* [SPEC] Add new v1::FloorMod operator

* Review Fix I

* [FUSED] Add reciprocal op

* Review Fix #1

* Move operator op::v1 -> op

* Fix serializer

* Review Fix I

* set output et

* set output et

* overwrote validate and infer

* Force AutoBroadcast to be specified at the op level since no default is correct for all ops.

* exports

* Added support mode for SpaceToDepth

* Added unit tests

* Fixed styles

* Revert changes in prototxt files

* [SPEC] Add auto_broadcast parameter to SquaredDifference

* Rename set_autobroadcast->set_autob

* [ONNX] Importer should use fused op for MatMul

* Fix a bug in fused matmul op

* Dont reshape matmul inputs to at least 2D any more

* LogSoftmax introduced

* Added LogSoftmax to serializer

* Fixed style

* Fixed CmakeLists style

* code review remarks introduced

* Code review remarks introduced

* Sketch of attribute walker

* Review comments

* merge error?

* Remove unused method

* simplify, make some ser tests work

* Don't look for keys that aren't there

* Factory registry, more ops visited, generic ser/dser start

* More merge

* cleanup

* Adapter for enums

* Compiler error

* Test of user-defined op

* Simplify enum name pairing

* Update distributed.hpp

* Review comments

* compiler error

* Direct access to non-primitive types from adapters

* Define and export type info

* attr enums, AvgPool*, vectors

* Cleanup

* some comments

* Allow type info to be used as a key.

* Don't leave output serialization shapes set.

* Auto adapter

* More ops, adapters

* Missing symbol

* Remove PartialShape and element::Type methods from visitor

* Fix type info

* Remove unused variable

* Simplify

* namespace error

* exports

* Uniform names

* Some better names

* More name cleanup, simplify visitor implementation

* Fix template, add test

* Revert serializer

* Add instantiations

* Work-around gcc issue

* VS exports

* VS exports

* windows export

* vs

* vs

* vs

* vs

* Simplify

* vs

* vs

* Add some missing attributes

* Missing factories

* Merge error

* Fix Add factories

* Missed type

* Round the right bit with denorms

* Rounding to inf

* Added reproducer for issue with broadcast v1

* Make reference broadcast work with V1 broadcast

Comparing size_t >= 0
|= for bools

* Add anchors attribute to RegionYolo operator.

* Make op doc more consistent.

* Make anchors optional attribute.

* Added support for ONNX's clip op in set_11.

* Registered clip in set_11.

* Code formatting.

* Added reshape.

* Changed to auto_braodcast.

* Code refactoring.

* Removed unnecessary import.

* Added constant sharing support

* Added unit tests for specialize_function

* Added parameter description

* Code style fix

*  WIP graph pass to lower ngraph to ngraph dialect

* resolved compiler errors

* - refactor ngraph-dialect to graph pass

* - fix compilation issue
- unit test passes

*  - style fix

* Addressed PR comments

* - move NgDialectConversionPass to anonymous namespace

* - use getModule() to access module inside the graph pass
- address PR comments

*  - fix failing unit test case for negative padding
- make builder as an object isntead of pointer to an object

* Address PR Comments

* Add folder to hold PDPD Fluid helper codes.
Planning to move code from PDPD bridge to this folder as part of code
cleanup restructuring.

* Move folder to src/ngraph/frontend/fluid

* implemented TopK:v1 downgrade

* Using v1 in onnx_importer; styles applied

* Fixed onnx_importer

* code review remarks introduced; fix clang errors

* Fixed problem with incorrect order of TopK outputs

* Code review remarks introduced

* Fixed output_order style

* Autodiff for atan2

* atan2 not supported on PlaidML

* Atan2 op