Ref values use the TargetRef to get the internal implementation
RegisterFromValFunction and ToNomsValueFromTypeRef were only used by
ref values at this point so these were renamed and simplified to be
more specific for ref values
We now do a recursive call which bottoms out with a ref.Ref for RefKind
Values. This means that we traverse into nested structures consistently.
The effect of this is that we get all the refs that the current chunk
references.
Ref Values now have a TargetRef() method that returns the ref.Ref of
the target the Value is referencing.
Note: This is a breaking change. In old code the Ref() of the Value was
the Ref of the underlying target.
Fixes#464
This makes the new typed serialization the default (the old
serialization is not used but the code has not been cleaned up yet).
Some things are no working in the new world:
Chunking - The compound list is not working correctly any more. The
Chunks method is having issues because it assumed things based on the
old implicit chunking.
Commit - uses a `Set(Commit)` which means that the parent commit is
embedded. We need to change that to be `Set(Ref(Commit))` so that the
parent commit is referenced instead.
The new serialization format use "t " as in typed. The rest of the
message is a JSON array describing the typed data. The type is
described by types.TypeRef
Fixes#384
Issues #281, #304
