Dont force some headers in http request

Signed-off-by: Frca <killerfrca@gmail.com>
Save in preferences hashed login password, not flat values

Signed-off-by: Frca <killerfrca@gmail.com>
Open last exam upon app open

Signed-off-by: Frca <killerfrca@gmail.com>
Fix release compile build and errors while uploading to Play Store

Signed-off-by: Frca <killerfrca@gmail.com>
Fix correct exam group setting after beeing registered

Signed-off-by: Frca <killerfrca@gmail.com>
Display ProgressDialog when registering to exam

Signed-off-by: Frca <killerfrca@gmail.com>