fix(ngModel): support milliseconds in time and datetime

[shahata]

Closes #8874

[btford]

I like this change except that it means that milliseconds are always displayed. I'm wondering if it makes sense to hide them unless milliseconds are non-zero or the step attribute has a value less than one.

[shahata]

I remember checking it and seeing that chrome does not display the milliseconds (and also seconds) if it's zero. I'll take another look in the morning.

[shahata]

@btford chrome indeed does the right thing when milliseconds is zero and does not display it: http://plnkr.co/edit/hYZwvnFSMBUBBHQiBvBn?p=preview

In case you believe it is better we do not include the .000 fraction regardless, I added another commit to this PR that does that. (it's not pretty and I don't like it though)

[shahata]

oooh I forgot about the case with step attribute having a value which is less than one. I'll add it later today unless you let me know you no longer want it :)

[btford]

@shahata thanks, looking into it now.

[shahata]

@btford I added the step case as well

[btford]

Thanks, @shahata. I'll take a look at this once #8912 lands. I don't think it'll take too much rebasing, but I wanted to give you a heads up.

[shahata]

Rebased with #8912
Just wanted to mention again that I'm not big on the second commit of this PR.
IMO we should always include milliseconds and only the first commit needs to be merged.

[btford]

After looking a bit more, I think your suggestion is good. I'm going to merge just 5811560 for now.

Thanks so much!

[btford]

Landed as 4b83f6c. Thanks!