HexLattice group corrections

ALL: in new_SymmetricNoise calculate only texture’s height, width will
be calculated after magnification.
ALL:  use ‘bilinear’ interpolation for imrotate(values should  stay
within the original texture’s range).
P3: To get predictable texture sizes after rotation, reduce width by 1
pix and use ‘crop’ for 120 deg rotation.
P3M1: variable rename