Issue with hemisphere part with textures

[Travis Cobbs]

I just realized that LDView's spherical code has detection of points due north or due south (with some leeway) of the center point of the spherical projection. If it detects these, it hard codes the V coordinate to be either -PI/2 (north) or PI/2 (south), then calculates a U point that is halfway between the U points of the other two points in the triangle. This doesn't produce "correct" output, but it's quite a lot better than what happens without the special case code. It doesn't have equivalent code for cylindrical projections.