bug fix
Merge remote-tracking branch 'upstream/master'

Conflicts:
	mixpanel/tasks.py
Add support for sending $ip data in PeopleTracker.
Add support for sending $ignore_time data in PeopleTracker.
print
Add union to the known events to be sent
Revert "print"

This reverts commit 6db93bac63e7d7320bc1781783dd9ed11621d491.
Add delete to the known action params