[GRASS5] QGIS / GRASS digit

[Radim Blazek]

I have improved the GRASS digit tool in QGIS. Three buttons are now 
supported with usual meaning known from v.digit, i.e

new line - left: new
            middle: undo
            right: close

edit - left: select/confirm
        rigth: release

See the prompt in status bar.

Also region and region edit was improved (status stored in setting, 
displayed/hidden if switched, EmitPoint used insteaad of CapturePoint).

Radim