Probably breaks curses build, but for gtk and Android
turn move and trade confirmation into a two-step process, making
board_commitTurn() non-interactive when called with a second
parameter. The old blocking util methods now return void and it's up to
the client code to interact (on the main thread) then re-call
board_commitTurn() if appropriate.
First attempt to stop blocking the jni thread: instead of returning a
password from a util_ method, have it include enough state that the UI
can return, put up a dialog, and then pass that state and the password
back and have them matched up again. I think this will work for the
remaining blocking Alerts too.
