Update coverage for js projects to run on CircleCI as well

[victorb]

15:47:33 <@daviddias> could you take npm run coverage from travis and add it to circle?
15:47:55 <@daviddias> https://github.com/ipfs/js-ipfs-api/blob/master/circle.yml#L7
15:48:08 <@victorbjelkholm> hm, doesn't it require bunch of configuration on the CI app's side as well?
15:48:27 <@daviddias> it was automatic when I did it for js-ipfs //cc @dignifiedquire
15:48:28 <@victorbjelkholm> like an env var with credentials?
15:48:55 <@victorbjelkholm> daviddias: could we maybe do that after I've finished the current pass with adding jenkins everywhere? 
15:49:10 <@daviddias> victorbjelkholm: sounds good

[daviddias]

One more request, do --provider coveralls (default is codecov)