basic mouse support, landscape mode, better mouse offset

[sirjofri]

mouse support: snarf and paste does not work, but you can use left and right click for doing things. use the last check box to enable this mode.

landscape mode: especially great for tablets. not tested when rotating the screens, but works fine when you start the app rotated.

better mouse offset: There's still a small offset, but it's much better than before. when it was 1cm before it is now more like 1-2mm. Still needs some thought.

will work on it.