GA4GH API v0.6.0a9

This is the first release that supports the separately pip-installable ga4gh-schemas module. It also includes some bug fixes, schema changes and some documentation updates.

Changes to ga4gh/schemas master branch since version 0.6.0a8 (Oct 26, 2016)

• Fixed bugs:
  • Fixed typo in get: /v0.6.0a8/variantannotationset/{variant_annotation_set_id}
  • Fix to be able to handle VCFs with genotype == ./.
• Upgrade to use protobuf release 3.1
• Introduced a pip installable schemas package called ga4gh-schemas. We have also
  created pip installable packages for a support library called ga4gh-common
  and a client library module called ga4gh-client.
• Introduced a schemas package release to Maven Central. We will be posting regular
  ga4gh packages for each official schema release to Maven going forward.
• Changed the name of the biosample terms to track be consistent with the use
  of camel-case and the underscore character.
• Added a new schema visualization tool to create UML diagrams from the schemas.
  The new diagrams can be viewed on the Schemas page in the Read The Docs documents.