Issue #381 clickable autocomplete

Made autocomplete to work with mouse.
I know the issue was created just a few hours ago. And was not yet approved by p-e-w. But I decided to implement it anyway. 
I think right click should either provide a menu or do nothing at all. Single click should copy the command in the prompt, double click should run the command. I quite sure about the double click though. Mouse usage is not supposed to be fast anyway.