git fetch --all can be annoying

[rconradharris]

If you have all your remotes stored in your ~/.gitconfig, then doing a fetch --all will cause everything to be synced, not what we wanted.

We should probably have the following behavior:

1. By default perform a git fetch against origin
2. Add an option which allows you to specific which repos to fetch
3. One value could be 'all'
4. Allow a ~./plyrc to specify this value permanently