Fixes #224 (#225)

Adds versioneer license explicitly (copied from the source file) and includes them in the manifest

Author: Russell Hay

Diff for: LICENSE.versioneer

@@ -0,0 +1,7 @@
+## License
+
+To make Versioneer easier to embed, all its code is dedicated to the public
+domain. The `_version.py` that it creates is also in the public domain.
+Specifically, both are released under the Creative Commons "Public Domain
+Dedication" license (CC0-1.0), as described in
+https://creativecommons.org/publicdomain/zero/1.0/ .

Diff for: MANIFEST.in

@@ -1,2 +1,4 @@
 include versioneer.py
 include tableauserverclient/_version.py
+include LICENSE
+include LICENSE.versioneer