Define MxLong/MxULong (#71)

* define MxLong/MxULong

The "long" type has different sizes on different platforms, and this may cause issues.

* use DWORD to match RegQueryValueExA arg

LEGO1/mxomni.cpp

@@ -123,7 +123,7 @@ void MxOmni::Destroy()
 }
 
 // OFFSET: LEGO1 0x100b07f0
-long MxOmni::Notify(MxParam &p)
+MxLong MxOmni::Notify(MxParam &p)
 {
   // FIXME: Stub
   return 0;