Made textbox.appendData() autoscroll to the bottom of the textbox. This
makes the debug window (and in the future the chat box) autoscroll as
expected. This will need to be reworked a bit so that if people are
scrolling they don't get annoyed by an autojump. For now, it's fine
though. On another note, I'm thinking of reworking the auto scrolling to
insert larger amounts of data, less frequently. Perhaps something like,
if you reach 3/4 of the way through, insert TCL_BUFFER_SIZE more lines.
or something like that. Bottom line is the performance is kinda shitty
on my older laptop and I'd like it to be better....