Apply volume to dialogs

Fixes #40

SourceX/storm/storm.cpp

@@ -58,6 +58,9 @@ BOOL SFileDdaBeginEx(HANDLE hFile, DWORD flags, DWORD mask, unsigned __int32 lDi
 	SFileChunk = Mix_LoadWAV_RW(rw, 1);
 	free(SFXbuffer);
 
+	Mix_Volume(0, MIX_MAX_VOLUME - MIX_MAX_VOLUME * volume / VOLUME_MIN);
+	int panned = 255 - 255 * abs(pan) / 10000;
+	Mix_SetPanning(0, pan <= 0 ? 255 : panned, pan >= 0 ? 255 : panned);
 	Mix_PlayChannel(0, SFileChunk, 0);
 
 	return true;