Add four X-* headers to mailer.py generated emails to allow clients to filter on them.
Add four X-* headers to mailer.py generated emails to allow clients to
filter on them.

* tools/hook-scripts/mailer/mailer.py:
  (MailedOutput.mail_headers):
    Add four headers:
      X-Svn-Commit-Project: the matching group name
      X-Svn-Commit-Author: the author
      X-Svn-Commit-Revision: the revision
      X-Svn-Commit-Repository: the basename of the repository

Patch by: J Robert Ray <jrobertray@gmail.com>
Tweaked by: me


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@878178 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion