Pyunc

Fixed

- Get Image Orientation (Patient) from first slice if not in the global header.

Added

- DICOM attributes can now be referenced by tag.
- PAT, IMG, PROC, and PLUT DICOM attributes are now read.

Fixed
- Can now read files where numeric values in DICOM header are empty.

Fixed
- Parse Image_Orientation_Patient_Coordinates and
Image_Position_Patient_Coordinates if they are in general file info.