Disable "Next" button if isNextEnabled() of first step returns false
Fix crash when logging at exit time
Add autologinUser to GlobalStorage.
Store log in ~/.cache by default
unsquashfs: Fix installation dir
Simplify unsquash code

- Merged UnpackEntry and UnpackStatusEntry. Created a entry_for_source dict.
- Removed dead code (update_copy_progress)
Store keyboard layout information in GlobalStorage.
Use libcalamares.utils.chroot_call in grub jobmodule.
Add SetTimezoneJob to locale viewmodule.
Create jobs in locale viewmodule.
Rough chroot call failure check
Make logging more useful

- Do not log progress percent but log job names.
- Log install failures.
Start the process before calling waitForStarted()
chrootCall: Log messages on failure, as well as command outputs
Merge with master