Color coded the server browser and added a filter for password protected games

This implements #4495 and applies the color code style from www.openra.net/games/ with a legend:

![image](https://cloud.githubusercontent.com/assets/756669/5157404/c3e91e68-7309-11e4-9c5c-22fa5eface1e.png)

Essentially a followup of https://github.com/OpenRA/OpenRA/pull/6983 whose game name + "(Password)" was a little too subtle and unpolished for my taste.
Red/orange/green is pretty horrible for colorblind users. You need some
other indication of the `protected` state as a fallback. (label? icon?)

On Mon, Nov 24, 2014 at 8:38 AM, Matthias Mailänder <
notifications@github.com> wrote:

> In OpenRA.Mods.RA/Widgets/Logic/ServerBrowserLogic.cs:
>
> > @@ -141,6 +149,20 @@ void RefreshServerList()
> >  			currentQuery = new Download(Game.Settings.Server.MasterServer + "games", _ => {}, onComplete);
> >  		}
> >
> > +		static Color GetColor(GameServer game, LabelWidget label)
> > +		{
> > +			if (!game.CompatibleVersion())
> > +				return Color.Gray;
> > +			else if (game.Protected)
> > +				return Color.Red;
>
> I stole the colors from ping and power labels which are already hard-coded
> in these bright colors that work on every mod UI design.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/OpenRA/OpenRA/pull/6993/files#r20767141>.
>