Lots of new tiny editor icons

- Several new icons for specific damage/status terrains
- New icon for light-emitting terrains (only shown in town)
- New icons for diagonal conveyors (even though they're still not implemented in the game)
- Some old icons updated, tweaked, or (in the case of crumbling) replaced
- Many new icons for developer use, including a complete set of letters and digits
- Choose button to select small icon for terrains that call a special node or have no special property (you select from a list of descriptions)

rsrc/graphics.exd/mac/CREDITS.md

@@ -21,7 +21,6 @@ rearranged a little:
 - dlogbtnsm.png
 - dlogbtntall.png
 - dlogpics.png
-- edbuttons.png (except the ones that are completely new)
 - edsplash.png
 - fighthelp.png
 - invenbtns.png (the coin was cropped from an item graphic)
@@ -98,4 +97,8 @@ still all original BoE graphics.
 
 In staticons.png, the last three rows (except the blue M shield) are from Blades of
 Avernum.
-The rest are original BoE graphics.
+The rest are original BoE graphics.
+
+Most of edbuttons.png is by ADoS. A few of the tiny icons are by Celtic Minstrel or
+unchanged from original BoE. Most of the palette buttons are based on original BoE. The
+blue button is unchanged from original BoE; the + button is by Celtic Minstrel.