Adjusts patch rotation to be aligned to a 90 degree increment relative to the landscape, adjusts UnscaledPatchCoverage such that it becomes a multiple of landscape quad size, and adjusts patch location so that the boundaries of the covered area lie on the nearest landscape vertices. Note that this doesn't adjust the resolution of the texture that the patch uses, so landscape vertices within the inside of the patch may still not always align with texture patch pixel centers (if the resolutions aren't multiples of each other).