Pass API key for vector tiles via Tangram globals parameter

[rfriberg]

Pass the required API key (see #332) (which may be overwritten in tangramOptions) to the included Mapzen basemap style for use with vector tiles. This may be done via global parameters in Tangram.js.

[nvkelso]

Related Cartography documentation work here:

• Add description on how to set API key per style tangrams/cartography-docs#2 (comment)

Example usage in Bubble Wrap:

• https://github.com/tangrams/bubble-wrap/blob/gh-pages/index.html#L224-L230

Because the Mapzen basemap styles are versioned, and this will be a breaking change with a new major version I will publish the new styles at my leisure (probably next week?), but we will need to land support for the API key in Mapzen.js (this issue) before I update the house style major versions config in Mapzen.js.

• https://github.com/mapzen/mapzen.js/blob/master/src/js/components/basemapStyles.js

[hanbyul-here]

also some related discussion ( Some concerns + ideas about how to integrate apiKey to tiles were raised while making L.Mapzen.apiKey : https://github.com/mapzen/mapzen.js/pull/321

I think it might be better to keep the way to pass the apikey, and make L.Mapzen.apiKey's jobs to handle all apikey underneath? (rather than making new spot to pass api key?)

[rfriberg]

@nvkelso - is the global parameter you're using for the basemap styles called sdk_mapzen_api_key or sdk_api_key. I'm seeing both in tangrams/cartography-docs#2 (comment) discussion.

Also, can you let us know when you publish (at least one of) the basemap updates so we can test?

[nvkelso]

@rfriberg we went with sdk_mapzen_api_key.

Some examples (using Github rather than posting to the S3 bucket):

• https://raw.githubusercontent.com/tangrams/bubble-wrap/gh-pages/bubble-wrap.yaml
• https://raw.githubusercontent.com/tangrams/refill-style/gh-pages/refill-style.yaml
• https://raw.githubusercontent.com/tangrams/walkabout-style/gh-pages/walkabout-style.yaml

[hanbyul-here]

closing with 7a29849