Correct a white space typo that results in test 5 failing when there
is no .config file.
add unittest driver - makes it easier to debug tests
Pull out constant linelimits and set them exactly once.  Hide the
value where possible using defaults.
Support line count of zero, (unlimited), and set the default to
unlimited.
port to python3
Merge remote-tracking branch 'rich/python3'
Insert whitespace
Fix configparser / ConfigParser

The import was right, the problem is that throughout the program, the
module ConfigParser was referenced. With Python 3, configparser was
imported, but the names would not match.

I now import ConfigParser as configparser and use Python 3 nameing in
the whole script.
Changelog entry
Version bump in setup.py