Added AddPreCompiledScript method to ScriptManager.

Done some work on lbsa71's simpleApp(hope he doesn't mind):
now have the avatar showing up and the terrain and his pulsating box (well except its not a box, as there seems to be something wrong with our PrimitiveBaseShape..DefaultBox() settings). 
Also noticed a few other problems that I had to work around, so these need looking into.

OpenSim/Region/Environment/Scenes/scripting/ScriptManager.cs

@@ -89,6 +89,14 @@ namespace OpenSim.Region.Scripting
                     break;
             }
         }
+
+        public void AddPreCompiledScript(IScript script)
+        {
+            MainLog.Instance.Verbose("Loading script " + script.getName()); 
+            ScriptInfo scriptInfo = new ScriptInfo(scene); // Since each script could potentially corrupt their access with a stray assignment, making a new one for each script.
+            script.Initialise(scriptInfo);
+            scripts.Add(script);
+        }
     }
 
     interface IScriptCompiler