Sourdough

Clean up code so we work when run out of ec2 now that we have a data center we care about.

* Stop trying to get boto ec2 connections when we aren't in ec2. Oops!

Try really hard to get a runlist and environment

* Load environment from `sourdough.toml` if we can't find a tag or knob file
* Load runlist from `sourdough.toml` if we can't find a tag or knob file
* Add default values for environment, region and runlist if they aren't in `sourdough.toml` and aren't in a tag or knob file.

Cope with rename on github from bigriver.sourdough to sourdough.

Allow specifying a chef server url instead of defaulting to Hosted Chef

First public version

* Begin.