[TW-226] Additional recurrence functionality: 1st and 3rd Tuesdays (for example)

_Cory Donnelly on 2010-08-02T19:57:25Z says:_

My municipality picks up recycling on the first and third Tuesday of every month and there's currently no way to create a single task recurring at this schedule.

"Aha," you might say, "you could schedule the task for every two weeks." This won't work, consider this month:

      August 2010


   Su Mo Tu We Th Fr Sa

32  1  2  3  4  5  6  7

33  8  9 10 11 12 13 14

34 15 16 17 18 19 20 21

35 22 23 24 25 26 27 28

36 29 30 31

The first Tuesday is the 3rd, (okay), two weeks later is the 17th (also okay) but two weeks after that would be the 31st (not okay).