* batch dot WIP.

* cpu backend refactor and unit tests pass.

* WIP.

* batch dot interpreter impelementation.

* minor clean up.

* more clean up.

* patching the gpu backends.

* added more tests, fixes, etc.

* fixed compile error.

* renamed batch dot to batch matmul.

* refactor WIP.

* fixes some tests and formating.

* more fixes.