Accessibility: option to prevent status line updates

Apparently some screen readers keep reading the status lines
at the bottom of the screen when parts of those change.
Add an option to prevent updates to those lines.

src/botl.c

@@ -213,7 +213,7 @@ bot2()
 void
 bot()
 {
-    if (youmonst.data) {
+    if (youmonst.data && iflags.status_updates) {
         bot1();
         bot2();
     }
@@ -436,7 +436,7 @@ bot()
 
     if (!blinit)
         panic("bot before init.");
-    if (!youmonst.data) {
+    if (!youmonst.data || !iflags.status_updates) {
         context.botl = context.botlx = 0;
         update_all = FALSE;
         return;

src/options.c

@@ -208,6 +208,7 @@ static struct Bool_Opt {
 #else
     { "statushilites", &iflags.use_status_hilites, FALSE, DISP_IN_GAME },
 #endif
+    { "status_updates", &iflags.status_updates, TRUE, DISP_IN_GAME },
     { "tiled_map", &iflags.wc_tiled_map, PREFER_TILED, DISP_IN_GAME }, /*WC*/
     { "time", &flags.time, FALSE, SET_IN_GAME },
 #ifdef TIMED_DELAY