Launcher for minishogi

[teytaud]

How to use this:

• install polygames as described here: https://github.com/facebookincubator/Polygames
• switch to branch "minishogilaunch" with << git checkout minishogilaunch >>
• check that everything works with << python -m pypolygames train --game_name=minishogi >>
• if everything is fine, << ./meta_minishogi.sh >>

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Motivation and Context / Related issue

How Has This Been Tested (if it applies)

Checklist

• The documentation is up-to-date with the changes I made.
• I have read the CONTRIBUTING document and completed the CLA (see CONTRIBUTING).
• All tests passed, and additional code has been covered with new tests.