Updated exmaple file to use latest hosted Leaflet version
Updated example script js file since it doesn't have to disable the pan control by default
Pan control defaults to false so it doesn't affect other plugins
Control container now has pan control class for better zoom altering

Previously if a pan control wasn't added to the map, the zoom control
would still be altered. Now a class is added to the control container
allowing for better control so that it's only altered if the pan control
is added.
Typo fix
Merge pull request #12 from grantlucas/grantlucas_default_visibility_update

Pan control defaults to false.