Human to set flags via dropdown

[GoogleCodeExporter]

Fix when a human checkmates an AI. Currently the AI gets a board where they
can't move, and so may just return a null move (that's what RnT does). 

There needs to be a way that either the human can signal checkmate
(tedious), or the AI can signal his own checkmate that the framework will
allow.

However, this is wrong because if the other AI doesn't signal checkmate,
then they lose. So, maybe have another way to signal "they checkmated me,
but didn't signal it." Which causes the other player to lose.

Original issue reported on code.google.com by twi...@gmail.com on 10 Apr 2008 at 1:44