Account for case where sequence of empty vectors
Merge pull request #31 from TreyLawrence/master

Frame#isEmpty wasn't working correctly for case of sequence of empty vectors
Added Frame.empty reg test
Fleshing out api
Continuing to hack on rfc2445 stuff
RRule DSL and index creation
Expanded rrule functionality
Added time dependency in tests where necessary
Refactor occurrence => counting, add conform function
Fix time rules
Made implicit conversion Weekday=>WeekdayNum work
Added tests; more robust heuristics for doing a backward conform
index get => raw, a bit simpler
Force count to be none in Index.make
Readying 1.3.0 for release
Upped version to 1.4.0-SNAP
Bug fix: need to make heuristic take longer number of periodsin counting of RRule
Clean up heuristic for counting recurrence backward
Getting reading for 1.3.1 bugfix release
Fixed another corner case, bah