Aborted mode
Changes
Added an abort function to HamsterGameController which sets the game to the aborted state.
This state is mostly like the Stopped state, with one exception: if another command is executed, it automatically changes to the stopped state and instead of a IllegalStateException, a GameAbortedException is thrown which - by default - is not shown as warning in the doRun method of a SimpleHamsterGame.
closes #11 (closed)