Support touch events on mobile

[bsudekum]

Many mobile devices will be able to support mapbox-gl-js. Right now on iOS8, it loads perfectly but the map does not respond to touch events:

cc @mourner

[mourner]

Hmm, I wonder what's causing the weird stripes on fills, @ansis?

[ansis]

what's causing the weird stripes on fills

My guess is that this is the fill antialiasing. Fill antialiasing is currently drawn with a line strip that is split with degenerate triangles. It looks like this isn't working right (maybe due to a precision issue). This should be fixed by using indexed lines: #668

[tmcw]

Now is the time: iOS 8 is out and rendering appears to be zippy on my iPhone 5S. Let's do this.

[mourner]

👍 I can look into this

[mourner]

Ongoing work in #749