fixed the level of detail seams !

st0op!d bug, returning the wrong height values at the seams, resulted in cracks. Fixed that, so the north-south connection now has its cracks eliminated. Now I need to do the textures correctly, THEN I can go to the east-west connect (+ textures), and THEN there's this little crack in the north-east corner because I don't have that neighbor (yet).

Phew, making a terrain is hard work!