0.10.0 beta 1

Added

• There are several new git.RefMutation constructors: SetRef, SetRefIfMatches, and CreateRef.
• git.RefMutation has a new IsNoop method to make it easier to check for the zero value.
• git.CommitOptions and git.AmendOptions have a new field: SkipHooks.

Changed

• *client.PullStream.ListRefs and *client.PushStream.Refs now return a map of refs instead of a slice.