Allow each edge to have different padding when fitting to bounds

[1ec5]

Camera.prototype.fitBounds() accepts padding and offset options for adding slop area (in pixels) around the fitted bounds. In mapbox/mapbox-gl-native#1783, I’m instead allowing each side of the bounds to have a different padding amount. It would be great to have this in gl-js as well.

Independent edge padding is necessary on iOS, because it’s customary to include about 32 points of top padding to make room for a translucent top bar overlay. In gl-js, it isn’t possible to express this behavior with a combination of padding and offset: you don’t want any padding to be added in the horizontal direction.

[jfirebaugh]

Added in #1675.

[benmcginnis]

Any chance of this happening?

[mohsen1]

This is blocking us from using MapBox GL. I submitted #3876 to resolve another blocker :)

[mollymerp]

@benjamintd @mohsen1 picking this up today -- I'll see what we can do!

[andrewharvey]

https://www.mapbox.com/mapbox-gl-js/example/mapbox-gl-directions/ is a good example of how it could be used. So that the fitBounds for the route ensure that the route fills the space to the right of the controls/instructions.