Init functions in MxMediaPresenter and LegoPalettePresenter (#121)

* Match MxMediaPresenter::Init

* LegoPalettePresenter::Init()

* LegoPalettePresenter: for now, use undefined4 type

LEGO1/legopalettepresenter.h

@@ -1,6 +1,7 @@
 #ifndef LEGOPALETTEPRESENTER_H
 #define LEGOPALETTEPRESENTER_H
 
+#include "decomp.h"
 #include "mxvideopresenter.h"
 
 // VTABLE 0x100d9aa0
@@ -27,6 +28,7 @@ public:
 private:
   void Init();
 
+  undefined4 m_unk64;
 };