Add support for nth with maps

[xzyfer]

This PR add support for nth with maps.

This can return the nth pair in a map as well. - http://sass-lang.com/documentation/Sass/Script/Functions.html#nth-instance_method

Fixes #643. Specs added sass/sass-spec#134.

[mgreter]

FYI: I get a success for this test with #1600 ??

[xzyfer]

@mgreter I'm not sure what you mean.

[mgreter]

I got a positive result with my test runner with that branch!
Wondering why now or put different, why did it not pass before?

[xzyfer]

I'm confused because the spec should have always passed. I'm not following
what your PR has to do with this old feature.
On 15 Oct 2015 8:04 pm, "Marcel Greter" notifications@github.com wrote:

I got a positive result with my test runner with that branch!
Wondering why now or put different, why did it not pass before?

—
Reply to this email directly or view it on GitHub
#647 (comment).

[mgreter]

Me neither, that's why I posted here, since it seems this is still in todo?
And now I see this is a PR and not an issue ticket (wrong number for todo test?)
Hmm, maybe something was off with my test suite, cannot check right now ...

[xzyfer]

As far as I can tell this spec (sass/sass-spec#134) as activated 11 months ago.