We aren't doing weeks, sets are the future.
Handle the case where we've never done a backup before.
support the DO_LVL0 option which lets you specify when a level 0 dump is done (every time, every other time, or on a specific set only). Introduce the idea of the trash dir to support the 'everyother' setting.
Merge branch 'master' of github.com:c0sco/autodump (bringing in README.md)