1.when changing photo of teacher or course in the backend the app gets
notificaton and replace the new pic 
2.bug fixes of broken connection with sql in thread 
3.when user deletes the pics manually the app checks them automatilcally
and redownload then by setting them in the db as not downloaded 
4.adding version to settings 
5.adding light weight constructors to Course,Teacher Class (id,idnumber) 
inorder to search by runtime with light objects