Initial version of libgames-scores

Fake pull request for initial review of libgames-scores.

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Instead of hiding the dialog, call `dialog.destory()`.  You should only hide a dialog after it's run if you plan to run the same dialog in the future (i.e. if you save the dialog in some variable so that you don't have to construct it again).  I like to create the dialog from scratch each time it's run, like you do here, but then you have to destroy it when you're done.