- Add sanity check for space remaining on disc.
    - Use flat % to determine when not to backup?
    - Only check space when resquashing?

- Implement options
    --resquash          manual resquash
    --rollback=<day>    rollback to a day of the week
    -c <config file>    specify path to different config

- Add logging

- Filter output from commands
    -mostly done, mksquashfs is still noisy

- Implement /tmp file for tracking custom mounts used with -R