Support more than 100 Gitlab hosted repos

Review Request #6037 — Created June 30, 2014 and submitted — Latest diff uploaded


Review Board


Newer gitlab versions do provide pagination support via a header.
See Gitlab v6.8.0+

Add a new method that follows the "next" rel if present in the link
header, and use this to fetch all repositories.

Tested on a gitlab 6.8.X deployment against a developer reviewboard. Was able to add a repository that's beyond the first 100 repos.