replace mysql with  queryDB(), and other adjustments to start upgrade fo...

...r ATutor 2.2

Hi Arun,
Finally got around to working on your module, starting the conversion over to ATutor 2.2 where mysql queries have been replaced with abstraction through queryDB(). Also looking at extending the module with CAS and LDAP, and turning it into a more general authentication module.

It would be appreciated if you wanted to help out.

greg