Add 'command' functionality to recipy-cmd

[robintw]

So we can do things like

recipy-cmd gui
recipy-cmd search
recipy-cmd editconfig

One command should basically create a folder where everything is how it was when the script was run: so it grabs the source from the git origin, checks out the correct revision and applies the diff. Not sure what this command should be called. Any ideas?

[robintw]

Done!