Load user settings in ST3

SublimeLinter tries to fetch settings from a wrong .sublime-settings file, since `__name__` format has changed. 

About the fix: clear_on_change and add_on_change methods seem to be not implemented yet, so no way to check if they are properly set up, but at least initial load should work. Maybe `name = __name__.split('.')[0]` should be changed to `name = __name__.split('.')[1]` (mind the index), if the plugin were to be cloned into non-standard directory.