Adding support for variable group sizes when executing an update. Design doc for this change is here: https://docs.google.com/document/d/1xGk4ueH8YlmJCk6hQJh85u4to4M1VQD0l630IOchvgY/edit#heading=h.lg3hty82f5cz
Testing done: Jenkins integration test passed. End to end tests passed. Feedback from https://reviews.apache.org/r/66192/ addressed. UI Change below:    Tests added for UI, Thrift change, and Pystachio changes. Moving this over to Github since reviewboard decided to act up. [ Full content available at: https://github.com/apache/aurora/pull/37 ] This message was relayed via gitbox.apache.org for [email protected]
