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

add test framework

stuff wired up

benchmark segfault for 5M nodes. fun

make traverse_nodes not recursive

print timings on benchmark

unit test for pass manager

Add input/output tensor information to nodes.

This is temporary and will be removed once upstreamed

Add support for 0D tensors to dot, clean up comments

* Adds a "make doc" command, outputting documentation in
  $BUILD_DIR/doc

update top sort to be linear rather than exponential complexit to b…

All tuples are expanded out to their component tensors.

Output: Describes one tensor output of an node
Input: Described one tensor input to a node, including the output supplying the value.

Finish type propagation in dot, add unit tests

This was removed because the previous eigen CMake spec forced a new CMake version
but that was taken out in a previous commit

add cmake finder for graphviz dot program and then conditionally comp…

A few binary elementwise ops