… delete_repo.

OkHttp changed API with v2.0.0, and the `client.open(url)` method no
longer exists:

"URLConnection support has moved to the okhttp-urlconnection module.
If you're upgrading from 1.x, this change will impact you. You will
need to add the okhttp-urlconnection module to your project and use
the OkUrlFactory to create new instances of HttpURLConnection"

https://github.com/square/okhttp/blob/master/CHANGELOG.md#version-200-rc1

Un-finalize a handful of classes.

Better FNFE from delete()

Update to OkHttp 2.0.0, which has a new OkUrlFactory

The original commit has too many whitespace noise changes.

Reference: #98

getCollaborators() only fetching the first page is a bug, so we should fix that too.