[feature] Add support for k and kk format parsing

[EzequielB]

k and kk parsing support behaves the same as H and HH, except for the value 24 that is treated as the 0 value for the HOUR field.
I had a concern about how to treat the 25 value, since moment("24:00", "HH:mm") is valid but moment("24:50", "HH:mm") is not; moment("25:00", "kk:mm") could be valid (setting the hour field to 1), but in the end that seemed counterintuitive.

Any thoughts are welcomed.
Hope this helps.

[ichernev]

@EzequielB change looks correct. Is this k token used in some other time library?

[EzequielB]

@ichernev, yes java's SimpleDateFormat uses it for example (http://docs.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html), and momentjs is also using it for formatting currently (not parsing).
(Just to mention my use case, I was willing to parse dates from image file names that Android vanilla cam generates, that uses k format for the hours).

[ichernev]

OK, makes sense. Can you please make a PR to our docs repo: https://github.com/moment/momentjs.com

[westy92]

Does the TypeScript definition file need to be updated as well?

[EzequielB]

@ichernev , docs were updated (PR moment/momentjs.com#400)
Let me know if all is ok.

[ichernev]

@westy92 I don't think so. Parse tokens are not part of the spec.

[ichernev]

Merged in 32438b4