Add mima plugin. In VersionedKeyValSource.scala, add back the old constructor for binary compatibility.
Add mima plugin. In VersionedKeyValSource.scala, add back the old constructor for binary compatibility.

And add deprecated warning.
Add more comments.
Resolve conflicts with origin.
Merge pull request #35 from reconditesea/klin_add_mima

Add mima plugin. In VersionedKeyValSource.scala, add back the old constructor for binary compatibility.