Implemented multi-user myplex accounts to allow fast swithcing between w...

...hich will preserve watch status on a per user basis.  There are still a few issues to work out when adding or removing users mostly relating to gui updating.  After a user is added or removed exit out of the setting area and return.  click on Switch user to select current user.  Will fix UI display issues and allow no user to be selected as well.  Was also thinking it may be nice to be presented with a user list when first entering PlexConnect as well.  Future enhancements can be a pin for when switching users.

There is still a bit of work to do on the UI, but the functionality is working.