fix crash due to memset()ing a non-POD

stepmania/src/InputFilter.cpp

@@ -19,7 +19,6 @@ static float g_fTimeBeforeSlow, g_fTimeBeforeFast, g_fTimeBetweenSlow, g_fTimeBe
 InputFilter::InputFilter()
 {
 	queuemutex = new RageMutex("InputFilter");
-	memset( m_ButtonState, 0, sizeof(m_ButtonState) );
 
 	Reset();
 	ResetRepeatRate();

stepmania/src/InputFilter.h

@@ -42,6 +42,7 @@ class InputFilter
 {
 	struct ButtonState
 	{
+		ButtonState() { m_BeingHeld = false; m_fSecsHeld = m_Level = m_LastLevel = 0; }
 		bool m_BeingHeld;
 		CString m_sComment;
 		float m_fSecsHeld;