Revert "IRCContact use the DATA API"
Revert "Revert "Merge pull request #1323 from delanne/IRCContact""

This reverts commit c203010282e3651673f98540b88c7302c7b71082.
Merge pull request #1333 from delanne/FixBadRevert

Revert "Revert "Merge pull request #1323 from delanne/IRCContact""
Merge pull request #1332 from delanne/revert-1323-IRCContact

Revert "IRCContact use the DATA API"
IRCContact consume 2 events:

    ('builders', None, 'builds', None, 'new') => A build is started
    ('builders', None, 'builds', None, 'finished') => A build is finished

When we will be able to get the list of changes for a build, the IRCContact must be updated.