Adjust -U to use a list instead of just a module name.

xenv/modules.py

@@ -87,5 +87,5 @@ def restore(env, name):
 
 
 # Restore modules from collection.
-def use(env, name):
-	return _module_command_function_pointer(env)(env, ["use", name])
+def use(env, modules):
+	return _module_command_function_pointer(env)(env, ["use"] + modules)