Use xdotool instead of keysharky server

This is because of this bug https://github.com/intarstudents/keySharky/issues/17.

Will revert when it is fixed.
Paste vim yank to other window.

Useful to send code to be evaluated by interpreters running in another terminal.
Filter history duplicates without loosing order.
search: keep the order in which engines were added.

Use an array for the engines and an associative array for mapping the engines to urls.