HyperRogue 13.1o: integration with the page that hosts the game at fredygames.com.

- control.cpp: in the browser the main loop never ends, so a request to quit (F10, the quit menu)
  did nothing. It now does what finishAll() does on the desktop (save_if_needed: records the score
  and, with an Orb of Safety, saves the game to continue later) and calls Module.onQuit, with which
  the host page writes the files to IndexedDB and restarts;
- hyperweb.cpp: when the page has a #this_wide element, the game uses all of its height too (before,
  outside fullscreen it took the window height minus 32 pixels, capped at 16:9).

Part of the source of the build served at fredygames.com (GPL-2.0-or-later, like HyperRogue).

--- a/control.cpp
+++ b/control.cpp
@@ -1652,12 +1652,26 @@
     }
 #endif
 
+#if ISWEB
+/* fredygames.com: the browser has no "exit"; when the game asks to quit (F10, or the quit menu),
+ * do what finishAll() does on the desktop (record the score; with an Orb of Safety, save the game
+ * so that the next start continues it) and let the host page restart the game. */
+void web_mainloopiter() {
+  mainloopiter();
+  if(quitmainloop) {
+    quitmainloop = false;
+    save_if_needed();
+    EM_ASM({ if(Module.onQuit) Module.onQuit(); });
+    }
+  }
+#endif
+
 EX void mainloop() {
   if(noGUI) return;
   lastt = 0;
 #if ISWEB
   initweb();
-  emscripten_set_main_loop(mainloopiter, 0, true);
+  emscripten_set_main_loop(web_mainloopiter, 0, true);
 #else
   while(!quitmainloop) mainloopiter();
 #endif
--- a/hyperweb.cpp
+++ b/hyperweb.cpp
@@ -223,6 +223,12 @@
     if(!d) return window.innerWidth;
     return d.clientHeight;
     });
+  /* fredygames.com: the host page gives the whole frame to the game (#this_wide fills it) */
+  else if(EM_ASM_INT({ return document.getElementById("this_wide") ? 1 : 0; })) {
+    vid.yscr = vid.yres = EM_ASM_INT({
+      return document.getElementById("this_wide").clientHeight;
+      });
+    }
   else {
     vid.xscr = vid.xres = vid.xres - 32;
     vid.yscr = vid.yres = EM_ASM_INT({