Add Inital Multi-Monitor Support

Initial support for multimonitor setups.
Support for up to 6 monitors with 1-6 players on screen 1 and 0-6
players on screen 2-6.
Currently the max amount of players is unchanged and participating
players are spread across all available screens.

Screens are extended horizontally. For fullscreen use with multiple
physical monitors one will have to use some kind of
surround-configuration. (AMD Eyefinity/nVidia Surround/etc.)

VocaluxeLib/Menu/CParticleEffect.cs

@@ -36,6 +36,7 @@ namespace VocaluxeLib.Menu
         public EParticleType Type;
         public float Size;
         public int MaxNumber;
+        public bool? AllMonitors;
     }
 
     public enum EParticleType
@@ -61,6 +62,8 @@ namespace VocaluxeLib.Menu
 
         public float Alpha = 1f;
 
+        public bool AllMonitors = true;
+
         public string GetThemeName()
         {
             return _Theme.Name;
@@ -302,7 +305,7 @@ namespace VocaluxeLib.Menu
             foreach (CParticle star in _Stars)
             {
                 star.Alpha2 = Alpha;
-                star.Draw();
+                star.Draw(AllMonitors);
             }
         }