#81 virtual go game

fixes #89 (window resizing)
fixes #101 (transparent circle in "augmented game mode")
closes #81

**Short summary:** Implemented a menu button that lets the user switch to "Virtual game mode".
Inside virtual game mode only one view shows the virtual board. The other one shows the augmented logo.
When hovering over the "virtual view" when "virtual game mode" is activated, a transparent stone is shown on a legal board position.
By clicking the move is executed and its the other players turn.

By default:  "virtual game mode" is disabled

![unbenannt](https://f.cloud.github.com/assets/3867700/931346/d9e9044c-002a-11e3-9e0e-401111017f20.PNG)