Add support for `time.time_struct` format about maya

[Miserlou]

(Internally it should be pretty simple, this works:

dt = datetime.fromtimestamp(mktime(struct))
maya_dt = MayaDT.from_datetime(dt)

the trick would just be getting a validator right.)

I can work on this if it's in scope.

[Miserlou]

And, I guess more generally, a load method would be useful as I have multiple sources of dates that could be in various string formats and python formats. Currently, Maya requires knowledge of the date type when instantiating, it'd be great if I could just throw whatever I've got at it.

[kennethreitz]

MayaDT.from_struct() would be very welcome (or would be it from_tuple?)

[kennethreitz]

@Miserlou well that's what maya.parse is for — it'll just magically take (almost) any machine-readable string and turn it into a MayaDT for you.

[kennethreitz]

If you can get everything into a string format, that would work well.