Add nimground faces to retro set. Clean up the TODO list.

ChangeLog.rtro

@@ -2,6 +2,7 @@
 	* wall/longtable/longtable_3.rtro.111.png: Make this face match the rest.
 	* indoor/table_*x*.rtro.111.png: Fix scaling of multitile tables.
 	* system/blocked_cyan.rtro.111.png: Add blocked_cyan retro face, since it is used in Navar
+	* ground/nimground/*.rtro.111.png: Added the purple nimground to retro set, since it is used in Scorn.
 
 2020-09-28 Daniel Hawkins
 	* ground/deep_swamp.rtro.11*.png: Fix transparency index.

TODO.rtro

@@ -4,16 +4,12 @@ Images missing faces in the retro tileset:
 ./ground/Winter/snow.111
 ./ground/Winter/snowroad2.111
 ./ground/Winter/snow3.111
-./ground/Winter/evil_ice.111
 ./ground/Winter/drifts.111
-./ground/Winter/evil_ice.112
 ./ground/Winter/snow2.111
 ./ground/Winter/snow5.111
 ./ground/Winter/ice.111
 ./ground/Winter/glacier.111
-./ground/Winter/evil_ice.113
 ./ground/Winter/snowroad.111
-./ground/Winter/evil_ice.114
 ./ground/Winter/ice2.111
 ./ground/Winter/istone.111
 ./ground/Weather/mountain_foilage.111
@@ -21,10 +17,6 @@ Images missing faces in the retro tileset:
 ./ground/Weather/mountain2_rivlets.111
 ./ground/Weather/mountain1_snow.111
 ./ground/Weather/mountain1_rivlets.111
-./ground/nimground/Nimground3_purple.112
-./ground/nimground/Nimground3_purple.111
-./ground/nimground/Nimground3_purple.114
-./ground/nimground/Nimground3_purple.113
 ./construct/Treehouse/treefort.x11
 ./construct/Treehouse/treefort3.111
 ./construct/Treehouse/treefort2.x11