Players and colors

[Fynx]

Currently there is a playerNameToColor map in Map.h.
Player class should have a 'color' attribute instead.
Right now colors can be distributed on random/depending on their index.

[Fynx]

Commit e2b0d47 contains most of the implementation. The only thing left is to change the ColorRect class in MapPropertiesManager to QWidget with custom paintEvent.