Add RRULE support for SETPOS with FREQ=DAILY

Summary:
Ref T10747. Most of these tests passed already.

Fix SETPOS with FREQ=DAILY and make that test pass too.

Test Plan: Unit tests now pass.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10747

Differential Revision: https://secure.phabricator.com/D16622