TemplateMatching: support images wider or taller than 16k pixels

[voxoid0]

Which translates to, use Point2D_I32 instead of Point2D_I16. Also it should check the image width/height that it is within the bounds of the supported size. When I tried to use a 32k+ wide image, i was getting out-of-bounds errors for when it found a template at around -32k; I then figured out it was because the X greater than 2^15 was getting wrapped around in the signed 16-bit int.

[lessthanoptimal]

That would be simple to fix by using an int. However template matching is very slow...

[lessthanoptimal]

I'm closing this issue since I think template matching on images that large is just impractical. Anyone should feel free to re-open this issue if they feel otherwise.