Aded Data Helper and Session Helper

These are two objects I find myself using a lot. I feel like the Class Name "Data" might be a bit too generic and would advise an alternate name, nothing came to mind right away.
I'm not sure what you mean. Currenlty this method returns true if the session, was/is destroyed and false if there's an error destroying the session.

So you can still do if( !Session::end() ){ /* something went wrong */ }