Create a generic way for passing constructor args to plugins

The old syntax didn't allow for any parameters except for services
listed in the ServiceList. Now, services loaded by other services can
also be made to use different ini sections or have additional paramters.
Syntax is: [<ExtraParam>@]...<DllName>[:<ClassName>]

OpenSim/Server/Base/ServerUtils.cs

@@ -242,6 +242,18 @@ namespace OpenSim.Server.Base
                     className = parts[2];
             }
 
+			// Handle extra string arguments in a more generic way
+			if (dllName.Contains("@"))
+			{
+				string[] dllNameParts = dllName.Split(new char[] {'@'});
+				dllName = dllNameParts[dllNameParts.Length - 1];
+				List<Object> argList = new List<Object>(args);
+				for (int i = 0 ; i < dllNameParts.Length - 1 ; ++i)
+					argList.Add(dllNameParts[i]);
+
+				args = argList.ToArray();
+			}
+
             return LoadPlugin<T>(dllName, className, args);
         }