Modernizes (python2/3 compatible code) the pydicom examples directory.

Added explicit __hash__ to PersonName3 class (python3.4+ needs explicit conversion for object).
Many places needed explicit bytes literal added to strings.
Unable to test dicomtree using Tix on my current platform.
Did not test interactive examples yet.
Modernizes contrib folder files.  Minimal testing done.

pydicom_PIL file cleaned up for line length, easier readability.
Merge branch 'modernize' into dev