cmd: holding down the scroll bar doesn't stop the output

Not only that, but extending the current implementation to do so would be a major PITA – it uses a ring buffer, and it would be necessary to keep track of the border between the top and the bottom of the buffer seperately from the visible portion, plus it doesn't store the width and height of the visible portion in the screen buffer. There'd be a ton of already-tangled arithmatic to change, too.

So probably it'd be best to get rid of the ringbuffer or at least abstract it.