Handle a <param name="game_id"> by passing it in to the C side as

Handle a <param name="game_id"> by passing it in to the C side as
argv[1], which in turn feeds it into the midend as a game ID. This
can of course take any of the forms supported by the native C
puzzles: a pure game parameter string, a params:description specific
game ID, or a params#seed random game ID.

[originally from svn r8095]