Feature/datetime

[antoyo]

No description provided.

[psyomn]

Looks good enough. It's nice to have basic time formatting out of the box, so this will definitely be useful.

[antoyo]

@psyomn: I was also wondering if I should implement the stuff marked with unimplemented!() and the locale-dependent stuff.
What do you think, @eloraiby?

[psyomn]

IMHO, it looks like basic functionality is there, and I don't think I've regularly used any of the unimplemented ones. We can implement them later.

One addition I can think of is perhaps rfcs for datetime formatting, kind of like how go does it, but I think that would add unnecessary clutter.