1.0 for 3.0
Test 3.0 only
Revert to public
Get MultiFormPurgeTask to actually work.

* `run()` is part of BuildTask not DailyTask
* `$session->delete()` doesn't return anything so the conditional will never be true
* Updated comments.
Merge pull request #15 from trev/patch-1

MultiFormPurgeTask fixes
Merge remote-tracking branch 'origin/1.0'