m_Do_Reset: OK (#35)

* m_Do_Reset: split and (some) decomp

decompiles:
- my_OSCancelAlarmAll()
- destroyVideo()

* mDoRst::reset(): decompile, plus some supporting code

* split DVD* functions to dvd.h

* mDoRst::resetCallBack(): decompile

libs/JSystem/JUtility/JUTXfb.cpp

@@ -1 +1,8 @@
-// ok
+#include "JSystem/JUtility/JUTXfb/JUTXfb.h"
+
+void JUTXfb::clearIndex() {
+    this->active_xfb_index = -1;
+    this->last_drawn_xfb_index = -1;
+    this->next_xfb_buffer = -1;
+    return;
+}