autoclose: Jump behind autoclosed items on tab press.

This is simulat to what eclipse does and very handy: If you enter e.g. sin(|);
and then  hit tab the cursor will move to sin();|. This also works if the cursor
is moved left/right on the same line.


NOTE: There's a memory leak, I don't know a clean way around. Any tip?
(see HACK comment in the code)