Add layout_user_status above layout_tracker_status. Displays username on layout_user_status
Change mServiceRun to bServiceRun since its a boolean!
Add isLoggedIn(), getUsername(), checkUser() in GpsLoggerApplication
Disable toggleBtnService if a user is not logged in
Display Register or Login Dialog when user is not logged in
Add IntentCodes
Change class based intent ids (i.e GpsManger.ACTION_LOCATION) to IntentCodes
Add onActivityResult in MainActivity. If the user presses back button or cancel then it should displaySignInDialog() again
Add buttonCancelPressed and buttonSubmitPressed
Checks username, password and password_confirmation
Check email in RegisterActivity
Add initial register() in RegisterActivity
Use JSONObjectRequest instead of StringRequest in RegisterActivity