Add optionsfull extended command

This is the previous, full options list. Adding it as
an extended command, so users can do

BIND=O:optionsfull

to go back to the old behaviour.

doc/Guidebook.tex

@@ -1498,6 +1498,9 @@ Open a door. Default key is `{\tt o}'.
 Show and change option settings. Default key is `{\tt O}'.
 Precede with the {\tt m} prefix to show advanced options.
 %.lp
+\item[\tb{\#optionsfull}]
+Show advanced game option settings.
+%.lp
 \item[\tb{\#overview}]
 Display information you've discovered about the dungeon.  Any visited
 level (unless forgotten due to amnesia) with an annotation is included,