(t-mouse-tty): Use with-temp-buffer. Add more

(t-mouse-tty): Use with-temp-buffer.  Add more
terminal types.
(t-mouse-lispy-buffer-posn-from-coords): Remove.  Use C
primitive...
(t-mouse-make-event-element): ...posn-at-x-y instead.
(t-mouse-make-event): Deal with Fedora Core 3.
(t-mouse-make-event): Don't sink the `stupid text mode menubar'.
(t-mouse-mouse-position-function): New function.  Use it instead
of advising mouse-position.
(t-mouse-mode): New minor mode.
(t-mouse-stop, t-mouse-run): Remove.  Use t-mouse-mode instead.