* Make code that depends on the legacy "type dispatch" mechanism optional.
* This code is fairly tied to a specific ~1.3 version and uses a legacy dispatch mechanism.
* Moving it and making it optional allows the project to build with PyTorch 1.6 and makes it possible for us to start building out a more modern interface mechanism in parallel.
* Some of the moved code will be brought back into the more modern path, but isolating it now lets this be done incrementally.
* Tests are left failing since the entire frontend is optional and the next step involves reworking the interface mechanism to get them to passing in both regimes.
* Fix a few bogons to get things building
* Add Dockerfile with pytorch
Also, I configure with:
-DCMAKE_PREFIX_PATH="/opt/pytorch/pytorch"
(which is where pytorch is installed in this container)
* Make a dep conditional.
Co-authored-by: stephenneuendorffer <stephen.neuendorffer@xilinx.com>
Stella Laurenzo