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/mxbitmap.cpp

@@ -0,0 +1,27 @@
+#include "mxbitmap.h"
+
+// OFFSET: LEGO1 0x100bc980
+MxBitmap::MxBitmap()
+{
+  // TODO
+}
+
+// OFFSET: LEGO1 0x100bca10
+MxBitmap::~MxBitmap()
+{
+  // TODO
+}
+
+// OFFSET: LEGO1 0x100bd1c0
+MxPalette *MxBitmap::CreatePalette()
+{
+  // TODO
+  return NULL;
+}
+
+// OFFSET: LEGO1 0x100bcd10
+long MxBitmap::Read(const char *)
+{
+  // TODO
+  return 0;
+}