add "Launch Game" to main menu

stepmania/src/smpackage/SMPackageUtil.cpp

@@ -1,6 +1,7 @@
 #include "stdafx.h"
 #include "SMPackageUtil.h"
 #include "Registry.h"
+#include "../ProductInfo.h"	
 
 void WriteStepManiaInstallDirs( const CStringArray& asInstallDirsToWrite )
 {
@@ -169,3 +170,22 @@ bool IsValidPackageDirectory(CString path)
 	return true;
 }
 
+void LaunchGame()
+{
+	PROCESS_INFORMATION pi;
+	STARTUPINFO	si;
+	ZeroMemory( &si, sizeof(si) );
+
+	CreateProcess(
+		NULL,		// pointer to name of executable module
+		PRODUCT_NAME ".exe",		// pointer to command line string
+		NULL,  // process security attributes
+		NULL,   // thread security attributes
+		false,  // handle inheritance flag
+		0, // creation flags
+		NULL,  // pointer to new environment block
+		NULL,   // pointer to current directory name
+		&si,  // pointer to STARTUPINFO
+		&pi  // pointer to PROCESS_INFORMATION
+	);
+}