Small tweaks for cryptsha512.
Fix for auto-tune using Intel GPU.
GPU: Abort job in case we hit the temperature limit set in john.conf.
Log GPU sensor readings at start/stop of session.
Allow 30 seconds grace time for a timer abort (-max-run-time) so we don't
lose the session save for slow/split-kernel formats.
Merge remote-tracking branch 'claudio/bleeding-jumbo' into bleeding-jumbo

* claudio/bleeding-jumbo:
  Fix for auto-tune using Intel GPU.
  Small tweaks for cryptsha512.
Avoid overhead in inner loop of split kernel OpenCL formats.
Avoid any type conversion between int and uint.
Reduce overhead in gpu_check_temp().
Clean up (cosmetic) of GPU code common for CUDA/OpenCL.
Show sm_5x (Maxwell) core counts correctly in --list=opencl-devices.
Ensure initial MPI/GPU logging in -fork children.