Can you add more date math examples to readme?

[bbookman]

I'm dim. I'm not 100% sure how to use this library to do something like (I'm shortcutting the syntax)

let christmas = Date(year: today().year, month:12, day:25)
let daysUntilChristmas = christmas - today ????? //give us some examples please

[naoty]

There is also a Xcode playground to understand how to use this library.

[bbookman]

Thanks, still documentation is the best option