implement all DLL exports (as TODOs)

Now we can use our own compiled LEGO1.LIB rather than one generated from the original. Also implements a script that tests them to help ensure future commits don't break them.

LEGO1/mxscheduler.cpp

@@ -0,0 +1,15 @@
+#include "mxscheduler.h"
+
+// OFFSET: LEGO1 0x100bf4f0
+MxScheduler *MxScheduler::GetInstance()
+{
+  // Intentionally empty
+  return 0;
+}
+
+// OFFSET: LEGO1 0x100bf500
+void MxScheduler::StartMultiTasking(unsigned long)
+{
+  // Intentionally empty
+}
+