Add graphicsview class.
Add backround image and CMake options.
Add exit button.
Add gray background to button.
Add exit signal to exit button.
Add background.
Set button text in constructor.
Add corner to button.
Button's hoover colours.
Add menu to a group.
Unselectable button in menu.
Add champaign and battle button to menu.
Button distance to menubuttongroup constructor.
Merge pull request #2 from Dgzt/menu

Menu