TODO List Recurrence

[allenporter]

Is your feature request related to a problem? Please describe.
Today there is no notion of recurring to-do lists.

Describe the solution you'd like
The storage format is a bit ambiguous, but i want to make it a similar design as recurring calendar events. We'll need a list view that handles a view including things like:

• only one instance of a recurring todo item is shown on the list at once
• need some window to decide which instance is shown
• need a rule for when to show a completed item (e.g. the new incomplete item doesn't exist yet)
• need a window for when to show the next/current incomplete item

Describe alternatives you've considered
Considering other ways to track completed status. I don't think its worth diverging unless we see a specific performance concern. May be worth benchmarking.

Additional context
Using Google Tasks behavior as a model.