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 feel that left click should do the same as pressing enter. 
And when someone is using mouse his right hand is on the mouse and not on the keyboard, so to execute a command after click he'll have to move it to the enter button.

But maybe we can put the command in prompt on right click.