fix use_inverse (aka wc_inverse) for curses

Highlighting for monsters shown due to extended monster detection and
for lava shown in black and white didn't work because that keys off
of 'iflags.use_inverse' (actually a macro for 'iflags.wc_inverse') and
curses wasn't enabling that window-capability option.  To be fair, it
was probably unconditional at the time the curses interface was first
developed.  It checked for whether a monster was supposed to be drawn
with inverse highlighting but wouldn't draw it that way because the
flag was always false.  Inverse b&w lava is relatively new and curses
hadn't been taught about it.

Various other things such as pets (if hilite_pet is on) and object
piles (if hilite_pile is on) get highlighted with inverse video when
use_color is off, regardless of whether use_inverse is on or off.
That's probably a bug.

win/curses/cursinit.c

@@ -810,6 +810,9 @@ curses_init_options()
 */
 #endif /* PDCURSES */
 
+    /* FIXME: this overrides explicit OPTIONS=!use_inverse */
+    iflags.wc_inverse = TRUE; /* aka iflags.use_inverse; default is False */
+
     /* fix up pet highlighting */
     if (iflags.wc2_petattr == -1) /* shouldn't happen */
         iflags.wc2_petattr = A_NORMAL;