Changing DUMPData parent class to DUMPReader class.
Changing DUMPData parent class to DUMPReader class.

For consistency with other structure format classes,
DUMPData now sub-classes DUMPReader, and code related to
reading/parsing the dump files moved to the DUMPReader class.

scikit-nano/scikit-nano,scikit-nano/scikit-nano,androomerrill/scikit-nano,androomerrill/scikit-nano