Add Mapzen provider

[DenisCarriere]

https://gist.github.com/sbma44/c005070ac76ece6aa259

[stirringhalo]

I'll have a couple pulls tonight for this one.

[stirringhalo]

Question Denis, I have Mapzen mostly working. However, when it fails to find a search result, the API returns:

{"type":"FeatureCollection","features":[],"date":1445969167316}

I'm not sure how best to handle this in mapzen.py (https://raw.githubusercontent.com/stirringhalo/geocoder/master/geocoder/mapzen.py). It ends up crashing on getattrs later on. I see Yandex.py needs similar handling but I cannot figure out how it does so.

Thanks!

[DenisCarriere]

@stirringhalo Perfect thanks! I'm going time to review it, so whenever that pull request comes in I will make sure it works.

[ebreton]

It looks like Mapzen works now. At least, the tests are passing for geocoding, reverse and multiple results 👍

Closing the ticket !