- various engine updates from Raze.

* removed refreshFreq variable and related code. This only got into the backend because of stupid interpolation code in some of the Build games which has long been removed.
* save FixedBitArrays as base64 in savegames.
* allow indirections in the string table - by prefixing the language string with '$$' the remaining text is interpreted as another string label to resolve.
* constexpr in palette code, also replacing #defines with enums.

src/common/engine/d_event.cpp

@@ -41,6 +41,7 @@
 #include "utf8.h"
 #include "m_joy.h"
 #include "vm.h"
+#include "gamestate.h"
 
 bool G_Responder(event_t* ev);
 
@@ -69,6 +70,8 @@ void D_ProcessEvents (void)
 			continue;
 		if (ev->type == EV_DeviceChange)
 			UpdateJoystickMenu(I_UpdateDeviceList());
+		if (gamestate == GS_INTRO)
+			continue;
 		if (C_Responder (ev))
 			continue;				// console ate the event
 		if (M_Responder (ev))