Undo apparent accidental @-color replaces in upstream TBA files. (#62)

I am guessing some script or tool used upstream is doing an unsafe
search-and-replace for '@' with TAB, and accidentally changing these.
They seem to have been creeping into the repo for years.

I produced this fix commit automatically with:
  sed -i 's|\t\([bcdgmnoruwyBCDGMRWY]\)|@\1|g' tba/*/*.*
...and then a few files' changes had to be undone.

I looked through all of the rest, and they look like correct fixes.

I also ran all the other letters, and they only make incorrect "fixes".

lib/world/wld/117.wld

@@ -697,8 +697,8 @@ D2
 E
 path flowers~
    The white tile path is clean swept and lined with gorgeous exotic flowers,
-including some 	rred	n, some 	yyellow	n, and some 	ggreen	n and a small amount
-of 	bblue	n ones.  
+including some @rred@n, some @yyellow@n, and some @ggreen@n and a small amount
+of @bblue@n ones.  
 ~
 S
 T 11716