What changed in EDuke32, build by build

stop playing sounds when entering the tile selector in 3d mode

second attempt at preventing extra wall points from being inserted on some walls with the batch point insert tool

in tile selector, make backspace set palette to 0

use object's current palette on tile selection screen and allow cycling object palettes from tile selection screen with - and =

use sc_XXX defines from scancodes.h instead of unlabeled hex scancodes when checking keystatus[]