Correct bash build script and clarify documentation.

build.sh

@@ -100,7 +100,7 @@ do
     length=$(echo $length | tr -d '\r')
     file=$(echo "$file" | tr '\\' '/')
     setBytes $start $length $file
-done < assets.txt
+done < $ASSETS_NAME
 
 echo "$GAME" > $ASSET_GAME_TYPE
 

docs/Probotector.md

@@ -72,7 +72,7 @@ replaced with "AC TEAM".
 
 Many of the sprites were changed to replace humans with robots.
 Additionally, some sprite animations were simplified, making many sprites
-identical, when they weren't identity in _Contra_ (US)
+identical, when they weren't in _Contra_ (US)
 
 * `sprite_27`, `sprite_28`, `sprite_3c` are equal
 * `sprite_29` and `sprite_42` are equal