Touching sky at certain tilt angles no longer causes infinite loop
Touching sky at certain tilt angles no longer causes infinite loop

If the movement toward the XZ plane is greater than 0.0, that means
the ray is moving _away_ from the plane (since the camera is assumed
to always be above it). This means the ray will never intersect the
plane, causing an infinite loop.

jstrait/webgl-city,jstrait/webgl-city