new completer for qtconsole. add a completer to the qtconsole that is navigable by arraow keys and tab. One need to call it twice to get it on focus and be able to select completion with Return. looks like zsh completer, not the gui drop down list of --gui-completer. This also try to split the completion logic from console_widget, and try to keep the old completer qui around. The plain completer that never takes focus back, and the QlistWidget completer. to switch between the 3, the --gui-completion flag as been changed to take an argument (plain, droplist, ncurses).