Add a SetQuery method to vtkDICOMParser.

This allows the parser to scan a file for certain attributes, and
to provide a yes/no answer as to whether a file matches a query.
Improve comments related to SpecificCharacterSet query.
Modify parser to do recursive querying of sequences.
Fix early exit behavior for when query fails.
Allow using a vtkDICOMItem as a parser query.
Add beginnings of a Query method for data sets.

Given an object that describes a query, this will return the result
of that query.
Change vtkDICOMDirectory to return arrays rather than ranges.

This provides more flexibility in how studies can be ordered.  In particular,
sorting studies by date can be more useful than sorting by patient in some
circumstances.
Add very crude query code to vtkDICOMDirectory.

This simply allows the results to be filtered, based on whether they
match the given query.
Use parser-based query in vtkDICOMDirectory.

In vtkDICOMDirectory, the parser is used as a scanner that only reads
data elements that are of interest.  This improves the efficiency.
Add a dicomfind program (still under development).
Flush dicomfind output after each directory.

This allows the user to see the results produced thus far.
Enable the "-o" option in dicomfind.
Make dicomfind return results in requested order.
Add library "dicomcli" for CLI utility functions.
Add "/" separator to query files for tag paths.
Use query to filter parser results in dicomfind.
In dicomfind, match ReferencedFileID to the filename.
Remove the Query method from Item and MetaData.

This is no longer needed, since the parser itself handles queries.
It might be brought back later, but note that its handling of nested
data sets (items) was never finished.