Make do_path display useful output
Use mark-and-sweep for garbage collection
Add command to find ancestor types of a set of objects
Add a shell command that pipes directly to sqlite
Add more files to .gitignore
Make it so that refs aren't repeatable
Display stats before and after a garbage collection run
Make path reversable
Make ancestor_types a little more friendly
Merge pull request #2 from cpennington/more-commands

New and improved commands