Add ability to find a proprietary SM file, for things such as ScreenHowToPlay

stepmania/src/ThemeManager.cpp

@@ -193,6 +193,7 @@ try_element_again:
 			{ "*.model", "*.sprite", "*.png", "*.jpg", "*.bmp", "*.gif","*.avi", "*.mpg", "*.mpeg", NULL},
 			{ "*.png", NULL },
 			{ ".set", "*.mp3", "*.ogg", "*.wav", NULL },
+			{ "*.sm", NULL },
 		};		
 		const char **asset_masks = masks[category];
 

stepmania/src/ThemeManager.h

@@ -17,7 +17,7 @@
 
 class IniFile;
 
-enum ElementCategory { BGAnimations, Fonts, Graphics, Numbers, Sounds, NUM_ELEMENT_CATEGORIES };
+enum ElementCategory { BGAnimations, Fonts, Graphics, Numbers, Sounds, SMFiles, NUM_ELEMENT_CATEGORIES };
 
 class ThemeManager
 {
@@ -41,6 +41,7 @@ public:
 	CString GetPathToG( CString sFileName, bool bOptional=false ) { return GetPathTo(Graphics,sFileName,bOptional); };
 	CString GetPathToN( CString sFileName, bool bOptional=false ) { return GetPathTo(Numbers,sFileName,bOptional); };
 	CString GetPathToS( CString sFileName, bool bOptional=false ) { return GetPathTo(Sounds,sFileName,bOptional); };
+	CString GetPathToSM( CString sFileName, bool bOptional=false ) { return GetPathTo(SMFiles,sFileName,bOptional); };
 
 	bool		HasMetric( CString sClassName, CString sValueName );
 	CString		GetMetricRaw( CString sClassName, CString sValueName );