Don't install backoff fuzzing tweens if the config says not to
Support less wonky ways of providing the config

I'm still not entirely certain why this is using an environment variable but
I can only assume it's some legacy thing that I haven't yet encountered.

Provide less wonky ways of providing the name of the config file.
Merge pull request #32 from rtilder/rtilder/minor-tweaks

Two minor tweaks prior to 0.8