Allow the writer to stream the data slice-by-slice.

This is to improve efficiency when writing large files.  If the
pipeline is capable of processing the data one slice at a time,
then only one slice has to be loaded into memory at a time.
Fix pipeline code that required VTK 6.
Fix static array that was needlessly declared double.
Add an option to explicitly set the ordering of written files.
Make sign of location match the sign of its dimension.
Update dictionary to the DICOM 2013 PS3.6 values.
Add missing space.
Add vtkDICOMFile class to centralize the IO.
Add feof and ferror check.
Make ferror and feof checks a bit more efficient.
Create the file object on the stack.
Check for valid handle before calling fclose().
Add RLE decompression to the basic reader.