MTime on Windows in only 32-bit even on 64-bit build

This issue was created automatically from an original Mantis Issue. Further discussion may take place here.

---

Even when building Windows 64-bit, the MTime ("unsigned long") is only 32-bit in length. What happens is that after long VTK execution the MTime will wrap around and cause problems in pipeline execution and the state of objects.

To fix this would require the creation of a type guaranteed to represent 64-bit integral values on all 64-bit builds. This type would then have to replace "unsigned long" throughout the code.