Added Paginator and RetryPolicy from google-genomics-utils.
The number of retries is a configurable and defaults to 3.

For code health: sorted the parameters on GenomicsConf and fixed imports.
Updated all the examples to use the access token instead of the client secrets.

The access token gets generated on the driver and propagated to all the workers.
Update README.md

Updated README to reflect the changes on the authentication flow.
Merge pull request #40 from elmer-garduno/master

Integrated several improvements from google-genomics-utils.