pyhdf: run 2to3
pyhdf/sdext.py: remove dead code
pyhdf: run reindent.py
pyhdf: regenerate swig code to be compatiable with python 3

regenerated with: swig -python -modern hdfext.i
pyhdf: get examples/vgroup working in python 3
pyhdf: get examples/txttohdf working in python 3
pyhdf: add print_function directives for python 2