Add initial UnrealScript support

The two samples are for two different UnrealScript generations:
MutU2Weapons is UnrealScript 2, US3HelloWorld is UnrealScript 3.

Signed-off-by: GreatEmerald <pastas4@gmail.com>

samples/UnrealScript/US3HelloWorld.uc

@@ -0,0 +1,10 @@
+class US3HelloWorld extends GameInfo;
+ 
+event InitGame( string Options, out string Error )
+{
+    `log( "Hello, world!" );
+}
+
+defaultproperties
+{
+}