recurrance takes a date recurrance expression
in near-English, and returns all the dates that
match. For example, entering "the second and
last friday of every month" might tell you all the
dates on which you should get paid. It is very
explible and easy to use, and complies to RFC
2445 RRULE implementations with the
exception of BYWEEKPOS, WKST, and the
start and end dates, which are done using the
code interface. It also supports an XML version
of RRULE, includes tests, and is completely
self contained.
