Fix conditions for VTK_PYTHON_EXE.

Check against the variable, not the string that the variable
evaluates to.
Fix warning from doubles stored in int array.
Add case folding for vietnamese.
Bump the version number to 0.5.3.

Changes since 0.5.2:
- Fix type for vtkValue::Matches() for FD values.
- improve cmake code for locating vtk.jar
- run java test even if VTK was built without testing
- run python tests with python if vtkpython not found
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.
Add a dicomfind program (still under development).