Adding Chinese checkers perf improvements.

This significantly decreases the size of propnets created from
these game descriptions and the time needed to create them, and
also has some benefits for backwards-chaining approaches like
the ProverStateMachine.

Also includes accompanying stylesheet changes to accommodate
the removal of explicit representation of blank cells.
Adding Chinese checkers perf improvements.

This significantly decreases the size of propnets created from
these game descriptions and the time needed to create them, and
also has some benefits for backwards-chaining approaches like
the ProverStateMachine.

Also includes accompanying stylesheet changes to accommodate
the removal of explicit representation of blank cells.
Merge pull request #2 from AlexLandau/chinese-checkers

Adding Chinese checkers perf improvements.