glvdebug: Enable 'Stop' button while replayer is paused.

glvdebug: Enable 'Stop' button while replayer is paused.

* Previously the user had to 'Continue' the replayer, then click 'Stop'.
* There a few things that can only take effect if the replayer is stopped (ie, changing replay settings), and most often the user will do this while the replayer is paused. This allows them to more easily stop and restart the replayer.
* Also disables all replayer buttons when the 'Pause' button is pressed, to ensure that the user doesn't put the system in a bad state while waiting for the replay to respond to the 'Pause' event.