simplify: Rescale positions to fit a [0,1] cube
simplify: Rescale positions to fit a [0,1] cube

Instead of just copying position data we now normalize it to fit [0,1]
cube by offsetting and uniformly scaling the vertices. This makes sure
that all errors are relative which makes it easier to tune thresholds.

zeux/meshoptimizer,zeux/meshoptimizer,zeux/meshoptimizer