implemented function responseFunction::sendResponse to provide a standard json message exchanging through procedures and object's methods
finished implementing User model
implemented Article model... maybe we'll have to implement a SuperClass that models will have to extend...maybe... and we'll have to rethink the data passing to the methods...datas will have to use this and don't pass nothing as param. Finally we should pass to query function json object insted of a separated params
implemented Category model
edited Article model following decisions taken in first issue
modified a lot of stuff.. Login now works using User model constructors
finished implementation of Models... Now I'll merge..hope will go fine
merged branch models_implementation in master