reload banner cache on reload songs

stepmania/src/BannerCache.cpp

@@ -168,7 +168,7 @@ void BannerCache::UnloadAllBanners()
 
 BannerCache::BannerCache()
 {
-	BannerData.ReadFile( BANNER_CACHE_INDEX );	// don't care if this fails
+	ReadFromDisk();
 }
 
 BannerCache::~BannerCache()
@@ -176,6 +176,11 @@ BannerCache::~BannerCache()
 	UnloadAllBanners();
 }
 
+void BannerCache::ReadFromDisk()
+{
+	BannerData.ReadFile( BANNER_CACHE_INDEX );	// don't care if this fails
+}
+
 struct BannerTexture: public RageTexture
 {
 	unsigned m_uTexHandle;

stepmania/src/BannerCache.h

@@ -20,6 +20,7 @@ class BannerCache
 public:
 	BannerCache();
 	~BannerCache();
+	void ReadFromDisk();
 
 	RageTextureID LoadCachedBanner( RString BannerPath );
 	void CacheBanner( RString BannerPath );