Add omit_buc -option

The option defaults to on, which is the old-style behaviour.
Turning the option off will never omit the "uncursed" -status
from inventory lines. This is pretty much required if users
want to use menucolors based on the BUC state.

include/flag.h

@@ -194,6 +194,7 @@ struct instance_flags {
     boolean deferred_X;       /* deferred entry into explore mode */
     boolean num_pad;          /* use numbers for movement commands */
     boolean news;             /* print news */
+    boolean omit_buc;         /* omit "uncursed" status in inventory lists */
     boolean mention_walls;    /* give feedback when bumping walls */
     boolean menu_tab_sep;     /* Use tabs to separate option menu fields */
     boolean menu_head_objsym; /* Show obj symbol in menu headings */