Image source should repeat across wrapped world copies

[anandthakker]

mapbox-gl-js version: master

Steps to Trigger Behavior

1. Create a map with an image source (and a raster layer to render it).
2. Pan the map past the international dateline.

Expected Behavior

A copy of the image appears after panning across the dateline in either direction.

Actual Behavior

The image only appears in the "original" world, and not in any of the wrapped "copies" of the world.