Adding control over the settings window from the keyboard.

First I define keyval each key that I will use. When the window detects that a key is pressed, fixed than a movement key, escape or enter, if so, begin the movement actions, otherwise, continues the search operation that was previously.
To perform the movement, first saves the coordinates of each icon depressible in a dictionary to revise motion when a key is pressed. When a movement key is pressed, it first sets which icon is selected and makes the underlying transactions to make the next move.
When selecting a new icon, this is painted in the colors of the character XO, and you have to deselect icon is painted in black and white.
If the key is pressed enter, performs the same action as when you click on an icon (this does not work if the search does not match the selected icon).
When the button is pressed scape, should be in a section returns to the home screen, otherwise closes the window.
Aren't these already defined in `Gio.KEY_*`?

**This is just an idea, not a code review**