RFR: 101: Add support for notifying an RFR thread when a PR is integrated

[Robin Westberg]

Hi all,

Please review this change that allows change integration notifications to be posted to a related RFR thread, if one is found. 

Best regards,
Robin

----------------

Commits:
 - 0a017c78:	Add new notifier modes
 - eaac7e44:	Add basic search for pull requests
 - 9ac1e608:	Move reply support into Email proper

Pull request:
https://git.openjdk.java.net/skara/pull/130

Webrev:
https://webrevs.openjdk.java.net/skara/130/webrev.00

Patch:
https://git.openjdk.java.net/skara/pull/130.diff

Fetch command:
git fetch https://git.openjdk.java.net/skara pull/130/head:pull/130