Fixes #130 Search Index now updates when m2m occurs

Haystack allows for a custom signal processor that listens
to signals. Implemented a M2MRealTimeSignalProccessor that
does naive real time index updating and listents to
m2m_changed too.
Implemented celery task for updating index.

It was taking too long to update object and
m2m relations. By using a celery task the time
was reduced to an aceptable level. Projects
that are not published are not longer added to
the search index.
Added new settings for tests.py

Travis build was failing I am changing
test settings to see if that fixes
removing unused param
Merge branch 'master' into issue/#130-search-index-out-of-sync-m2m
Trying to debug a celery problem
Added new setting into settings/test.py for celery

to use CELERY_ALWAYS_EAGER=TRUE.
Merge branch 'master' into issue/#130-search-index-out-of-sync-m2m
Merge remote-tracking branch 'origin/issue/#130-search-index-out-of-sync-m2m' into issue/#130-search-index-out-of-sync-m2m
Merge pull request #135 from rapidsms/issue/#130-search-index-out-of-sync-m2m

Search Index now updates when m2m occurs