add liveness pass

Simplify expression construction for tests.

* Simplify external function use.

* By default, release original function.
Optional argument to delay release.

add naming of tensors and tensor views
add visualization pass
add graph dump pass

Fixes for building with reference OS in docker image

remove class Op and merge functionality with Node

Changes to allow build (in docker run) to run as the user, not root, so BUILD directory is easily removable.

Function execution

CMake: Replace a previously missed instance of 'git am'

CMake: Use 'patch' instead of 'git am'

Git invocations without an available gitconfig (ex. a test environment)
will fail whereas patch should always work. This adds a build dependecy on patch.

fix namespace collision in runtime test

VM for interpreting ops

* Implemented binops/unops with different return type from args

* Implemented generic bases class for comparison and arith ops, changed current comparison ops to subclass it

* Added a TraitedType for booleans

* Moved arith and comparison ops to separate header files from `op.h`

Change Input/Output to instances in node rather than shared_ptr

CMake: Ninja fixes and MKLDNN integration

Add mechanism for pass dependency checking

Tensors with eigen implementations for addition, multiplication

Start of external function calling support

Add memory layout and liveness passes.

* Fixed the paths in the include statements

* absolute path include, relative to /src

* fix invalid use of incomplete type

* Fixed a compilation error.

Add pass manager

Currently MKL-DNN isn't supported on this platform

Add Doxygen support