- adds config get and config set commands
- supports arbitrary k/v strings set at top and host level
- supports writing an updated config, preserving comments
- supports mostly lazy evaluation of yaml
Also define a handful of utility methods:
- `New(owner, repo)`
- `FullName`: the name slash owner pair
- `FromFullName`: parse the name slash owner pair
- `FromURL`: parse a GitHub.com URL
- `IsSame(r1, r2)`: compare two repositories