Work so far on de-Eigenization

* move replace_node to util

* static run_matchers_on_nodes_list

* switching to map

* formatting

* addressing Scott's feedback and fixing warnings

* more pattern matcher refactoring

refactoring cont'd

* Add numpy_transpose to the builder for numpy-stype transpose operations

* fix docstring

* make sure to throw the error

Merge branch 'aprocter/de-eigenize' of github.com:NervanaSystems/private-ngraph-cpp into aprocter/de-eigenize

* add json lib 2.1.1

* add json serialization of graph

* cleanup

* enhance unit test

* remove FunctionProvider class and replace with virtual get_function() in Node

* remove json code from element_type

* move serialize to be directly in the ngraph namespace. cleanup header file.

* add cname check to element::operator==

* add using json = nlohmann::json

* Autodiff for abs

* Formatting, more tests for abs

* Cos autodiff; also a clarifying comment in the abs test

* Forgot cos.cpp

* Sin autodiff

* Again, forgot to add sin.cpp  :/

* Tan autodiff

* Minor formatting tweak

* Commit partial work on select backprop so I can run valgrind on the server  :/

* Fix boolean thingy so it works on Linux

* Autodiff for ceiling, convert (untested), floor, sign. Fix unit test for tan. Implement ceiling, floor in VM.

* Fix bug in abs/sign unit test ranges

* Add multiplicative inverse and square-root ops (needed for hyperbolic trig autodiff)

* Better formula for sqrt adjoints

* Autodiff for hyperbolic trig ops

* Forgot to add cpp files for hyperbolics

* Remove inv (don't need it after all); also formatting (oops)

* fix bug with Convert autodiff

* Autodiff for concat

* Restore the accidentally-commented-out unit test for abs

* Formatting

* Fix 'unordered_map.at' exception when Adjoints::Adjoints visit a node that has never been add_delta'd; remove workarounds for that bug

* Fix erroneous 'not implemented' docstring for op::Not

* Autodiff for sum

* Checking in broken support for replace_slice so I can test it with valgrind on the dev box

* Fix unit test bug with tensor initialization; formatting

* Implement replace-slice in CPU backend

* Autodiff for Slice and ReplaceSlice

* Tweak docs for ReplaceSlice

* Remove no-longer-needed cast of arg list to runtime::TensorView

* Start of pattern matcher

recursive graph matcher, pattern node

add matcher.cpp

add files for matcher, graph_rewrite

add const to on_match_class

fix comp errors

reshuffle pattern matching code across corresponding files

fix comment

run clang-format

graph_rewrite replace_node

getting simple test cases to work

op/pattern.cpp

toward graph_rewrite tests

older matcher API

before clean up tests

before rebase

build bbrks

more tests

clean up

more clean-up

more cleanup 2

more clean up 3

clean up 4

clang errors

clang errors2

apply code format

move match_class to matcher

major clean up after moving match_class to matcher.cpp

removing tracing changes

rebased as of 11/8

make matcher use i/o descs to traverse the graph; change replace_io

switching to io tds

graph_rewrite tests fail

all tests pass

formatting

unhandle outputs explicitly for now

reset permissions back to 0644; bad bad windows

fixes after rebase

* fixes

* addressing Scott's feedback