Get cursor keys working in chat window

[bert_the_turtle]

Really humble request: it would be nice to improve the chat input a bit. Like adding the ability to move the cursor around with the left and right arrow keys so you can fix a typo at the beginning of the line without having to reenter it. Bonus would be stuff like the Home and End keys to move the cursor to the line ends, the Delete key, and maybe scrolling the backlog with Page Up/Down.

Standard apology: Sorry if this has been posted before, I did search, but maybe not enough.

[shinygerbil]

I would also like to see the speed of scrolling (when you press the arrows) be a bit more than a snail's pace.

[kentuckyfried]

Hear, hear on all listed! Chat functions are pretty wonky.