Enable Travis-CI
Remove Python 2.6 from Travis, format YAML properly
Add Travis-CI build status to README
Add notifications to travis configuration.

Added margarine-dev mailing list and #margarine on freenode to travis
configuration.
Merge branch 'master' into test/travis
Remove mailing list notifications from travis.

Seems that using google groups for our developer mailing list is not
compatible with travis-ci's notifications.  Trying to send an email to
the google groups list from travis is blocked due to membership being
required.  Also, when trying to add the notifications email for travis
as a member we're alerted to the fact that it too is a google group and
can't be added to a google group.
Quiet output of pip as it's not important during a test.