Document keys in GlobalStorage
Do not let the user pick a partition type when creating a partition of a GPT disk

Fixes #27
FillGlobalStorageJob: Add the partition UUID to global storage
Basic fstab module

Misses the 'options' finetunes

Bug #66
Coding style
Spaces fixes
Begin unsquashfs module, port copy operation from Thus.
Use temp dir for mounting squashfs image.
Count the files in the squashfs image without piping to wc -l.
Unthreadify FileCopy in unsquashfs.
Better call to rsync in unsquashfs.
Use named tuples in unsquashfs.
Improve error reporting for Python jobs.
Correctly report exit status from Python modules.
Fix some lousy error handling
Improve readability.
Make fileCopy in unsquashfs a single function