fix travis tests

[mapsam]

Working on fixing the tests in travis - currently running into Maximum call stack size exceeded errors during our vendor script, which takes a long time.

[mapsam]

Huzzah! Removing our custom mapbox.js bundle and just going straight to the CDN has improved travis speeds immensely. @wboykinm @SwampGuzzler

Unfortunately, the topojson client is a bit different these days and an attempt at babelifying it doesn't result in code that works in browser, and still tries to fs.readFileSync. I've copied over our current topojson_package.js in the lib/ so we can continue to use it until we can dig further. cc @jczaplew

TODO:

• fix codeship
• get @SwampGuzzler's PR working toggleLayers update #256

[mapsam]

Ah, just a path change needed for topojson - thanks @SwampGuzzler!

[mapsam]

Woo! This is good to go.