Enabling the vtkFileSeriesReader for vtkMOCReader and vtkMHTReader.

This allows both the vtkMOCReader and the vtkMHTReader to support
reading a series of files and give basic time support for
multiple files.
Merge pull request #17 from aashish24/POP_fileseries_readers

Enabling the vtkFileSeriesReader for vtkMOCReader and vtkMHTReader.