Merge pull request #1 from ajwdewit/develop

Develop
Replaced relevant strings with byte arrays. The URL response is bytes,
which are incopatible with strings in python3. The new syntax b"..."
should be supported by Python 2.6,2.7,and 3.0+. Tested with 2.7.8
and 3.4.1.
Merge pull request #2 from marekpetrik/cmpt_py3_nasapower

Python 3 compatibility for nasapower.py