Added a tool for parsing JSON URL endpoints and reading out fields.

Review: https://reviews.apache.org/r/9331

git-svn-id: https://svn.apache.org/repos/asf/incubator/mesos/trunk@1443173 13f79535-47bb-0310-9956-ffa450edef68
Added a tool for "applying" a review from Review Board.

Review: https://reviews.apache.org/r/9332

git-svn-id: https://svn.apache.org/repos/asf/incubator/mesos/trunk@1443174 13f79535-47bb-0310-9956-ffa450edef68