Implement/match remaining MxSoundManager virtual functions (#250)

LEGO1/mxwavepresenter.cpp

@@ -16,3 +16,21 @@ void MxWavePresenter::Init()
 	m_unk66 = 0;
 	m_unk68 = 0;
 }
+
+// OFFSET: LEGO1 0x100b2440 STUB
+void MxWavePresenter::VTable0x64()
+{
+	// TODO
+}
+
+// OFFSET: LEGO1 0x100b2470 STUB
+void MxWavePresenter::VTable0x68()
+{
+	// TODO
+}
+
+// OFFSET: LEGO1 0x1000d6b0
+undefined MxWavePresenter::VTable0x6c()
+{
+	return m_unk68;
+}