Enforce creation of unborn branch test coverage
Protect Signature creation from components containing '\0'
Protect Signature creation from invalid parameters
Protect Commit creation from message containing '\0'
Protect TagAnnotation creation from name or message containing '\0'
Protect TagAnnotation creation from invalid parameters
Refactor Marshalers
Split Patch and TreeChanges generation

Remove Patch from TreeChanges
Make repo.Diff.Compare() generic
Introduce EncodingMarshaler.Cleanup()
Make string marshaling either lax or strict
Enforce repo.Network.Push()  test coverage
Allow push APIs to set packbuilder parallelism
Introduce blob FilteringOptions for content stream

Get the content of a blob as it would be checked out to the
working directory via the filters.
Expose Push progress reporting
Clean up cancellation patterns in callbacks and other small cleanups.
Fixed a typo.
Merge branch 'upstream_vNext' into vNext