fix crash when the quickload y/n is ack'ed within the same frame

Fixes #14.

Originally the game faked the Escape key being pressed to force menus
to be opened, so I changed that to be a specific variable.

Next, MNU_Dialog has changed to a ternary return: yes, no, no-answer.
This pulls the input handling into one place. Also, I think perhaps the
custom draw callback was intended to have different call phases. Needs
careful testing to verify my changes.

Also I turned back on demo record/play because I needed to check the
change with regards to the menu loop showing menus.

src/game.c

@@ -1630,7 +1630,7 @@ NewLevel(VOID)
             if (DemoModeMenuInit)
                 {
                 DemoModeMenuInit = FALSE;
-                KEY_PRESSED(KEYSC_ESC) = TRUE;
+                ForceMenus = TRUE;
                 }
             }
 
@@ -2206,7 +2206,7 @@ MenuLevel(VOID)
     // go to ordering menu only if shareware
     if (FinishAnim)
         {
-        KEY_PRESSED(KEYSC_ESC) = 1;
+        ForceMenus = TRUE;
         ControlPanelType = ct_ordermenu;
         FinishAnim = 0;
         }
@@ -2266,7 +2266,7 @@ MenuLevel(VOID)
         // force the use of menus at all time
         if (!UsingMenus && !ConPanel)
             {
-            KEY_PRESSED(KEYSC_ESC) = TRUE;
+            ForceMenus = TRUE;
             MNU_CheckForMenusAnyKey();
             }
 
@@ -3904,7 +3904,7 @@ int app_main(int argc, char const * const argv[])
                 }
             }
         else
-        if (FALSE && Bstrncasecmp(arg, "dr", 2) == 0)
+        if (Bstrncasecmp(arg, "dr", 2) == 0)
             {
             //NumSyncBytes = 8;
             DemoRecording = TRUE;
@@ -3919,7 +3919,7 @@ int app_main(int argc, char const * const argv[])
                 }
             }
         else
-        if (FALSE && Bstrncasecmp(arg, "dp", 2) == 0)
+        if (Bstrncasecmp(arg, "dp", 2) == 0)
             {
             DemoPlaying = TRUE;
             DemoRecording = FALSE;
@@ -4572,7 +4572,7 @@ FunctionKeys(PLAYERp pp)
             KEY_PRESSED(KEYSC_F2) = 0;
             if (!TEST(pp->Flags, PF_DEAD))
                 {
-                KEY_PRESSED(KEYSC_ESC) = 1;
+                ForceMenus = TRUE;
                 ControlPanelType = ct_savemenu;
                 }
             }
@@ -4583,7 +4583,7 @@ FunctionKeys(PLAYERp pp)
             KEY_PRESSED(KEYSC_F3) = 0;
             if (!TEST(pp->Flags, PF_DEAD))
                 {
-                KEY_PRESSED(KEYSC_ESC) = 1;
+                ForceMenus = TRUE;
                 ControlPanelType = ct_loadmenu;
                 }
             }
@@ -4595,7 +4595,7 @@ FunctionKeys(PLAYERp pp)
             KEY_PRESSED(KEYSC_F6) = 0;
             if (!TEST(pp->Flags, PF_DEAD))
                 {
-                KEY_PRESSED(KEYSC_ESC) = 1;
+                ForceMenus = TRUE;
                 ControlPanelType = ct_savemenu;
                 QuickSaveMode = TRUE;
                 }
@@ -4615,7 +4615,7 @@ FunctionKeys(PLAYERp pp)
                 else
                     {
                     KB_ClearKeysDown();
-                    KEY_PRESSED(KEYSC_ESC) = 1;
+                    ForceMenus = TRUE;
                     ControlPanelType = ct_quickloadmenu;
                     }
                 }
@@ -4628,7 +4628,7 @@ FunctionKeys(PLAYERp pp)
     if (KEY_PRESSED(KEYSC_F4))
         {
         KEY_PRESSED(KEYSC_F4) = 0;
-        KEY_PRESSED(KEYSC_ESC) = 1;
+        ForceMenus = TRUE;
         ControlPanelType = ct_soundmenu;
         }
 
@@ -4674,7 +4674,7 @@ FunctionKeys(PLAYERp pp)
     if (KEY_PRESSED(KEYSC_F10))
         {
         KEY_PRESSED(KEYSC_F10) = 0;
-        KEY_PRESSED(KEYSC_ESC) = 1;
+        ForceMenus = TRUE;
         ControlPanelType = ct_quitmenu;
         }
 
@@ -4743,7 +4743,7 @@ VOID PauseKey(PLAYERp pp)
                 }
             else
                 {
-                KEY_PRESSED(KEYSC_ESC) = 1;
+                ForceMenus = TRUE;
                 ControlPanelType = ct_quickloadmenu;
                 }
             }