Added professors to the course model;
Increased lenght of session varaible;
Added user groups into the user api call;
JSON error; Fixed;
Removed Groups API. Redundant;
Cleaned up the Authentication system a bit more;
Removed uncessary files and imporved code.
Updated DB files;
Adde a simple welcome text in the homepage;
Groups bug fix;
Got rid of unecessary code;