Added world loading and other various improvements

Model.cpp

@@ -158,10 +158,6 @@ void Model::Optimise(ObjGroup *t)
 	}
 }
 
-Model::~Model(void)
-{
-}
-
 void Model::draw()
 {
 	for (auto &g : groups)
@@ -381,3 +377,11 @@ void Model::unload(Model* model)
 		}
 	}
 }
+
+Model::~Model(void)
+{
+	for (auto m : cache)
+	{
+		delete m.second.first;
+	}
+}