* updated to work with llvm 8.1 that tensorflow is built with

* sane extensions on the mac

* not doing rpath on apple

* apply style

* inplace compute

* fix warnings

* address bob's feedback

* bob's feedback 2

* bobs feedback 3

* address bob's feedback 4

* remove reference to ngraph core code from codegen. add stand-alone implementations of needed funcions

* fixed potential pointer leak

* clean up file_util

* more file util cleanup, removing unused functions

* interpreter works on mac

* CPU and INTERPRETER build and pass unmit tests on macos

* move get_directory to file_util

* cleanup

* switch to using has_class for op::Skip

* apply format

* adding constant propagation pass

* adding test/constant_propagation.cpp

* template make_constant_reshape function

* code review feedback

* add missing files

* serialize logic for reverse_sequence

* Added serializer support for Softmax

* Fix bug with concat for 0-size tensors

* Simplify test for zero-length axes, per PR comments

* [doc] Fix code snippet in derive-for-training

* Fix another code snippet in derive-for-training

* add assert to make sure we don't replace unreachable nodes

* fix unittest failures

* sparsity fix

* fix mkldnn rpath

* fix compile warning

* close backends when exiting

* set backend output directory of backends to the ngraph output directory

* Aprocter/patch patch (#1119)

* Move more rpath stuff inside if(NOT APPLE)

* fix repatch problem with mkldnn library

* add updated patch command for older versions of cmake

* loop kernel + tests

* remove commented out code

* remove commented code; add comments

* copy_with_new_args +test

* add comment

* fix comp errors

* Move to depth-first serialization of graph for better cache behavior

* Added comment

* Force 64 byte stack alignment to avoid crashes from unaligned AVX loads/stores

* Revert "Force 64 byte stack alignment to avoid crashes from unaligned AVX loads/stores"

This reverts commit 84346420fbd0fbd5d05a4a1e8f5fae12bdc7348b.

* revert to breadth-first serialization

DEX Part 2

* enable more gpu ops test

* add reverse_sequence

* fix bugs, compiled

* fix index bug

* fix bug and clang format

* correct function name

* clang format

* remove extra ;

* remove tests from skip list

* add backward support, skip tests

* add back template<> line

* remove unecessary lines in kernel

* optimized strided convolutions

* clean up debug messages

* format fixes

* more tests

* even more tests

* adapt to resnet-50.v1

* fix format errors; remove changes from diff PRs

* enable cse for reduction ops

* reduction tests

* - Added graph pass for fusing RNN op across layer
- Added test case for inter v/s cpu for verifying layer fused RNN
- more sanity checks in the RNN fusion graph pass
- added support to replace the recurrent cell state correctly in the fused RNN op

* Fixed multi layer rnn fusion unit test failure

* Addressed PR comments

* enable tests

* add funciton call

* working version

* remove test from ski list

* remove comments within body of function

* change to emit each op exactly once

* update code per review comments

Also, formatting fixes