- add {now} and {utcnow} to context
- use correct file encoding writing to config file. NOTE: If you are
using Python2 and want to use UTF-8 encoded characters in your
config file, you need to update ConfigParser like using 'pip install
-U configparser'
- leave current\_version in config even if available from vcs tags
(was confusing)
- print own version number in usage
- allow bumping parts that contain non-numerics
- various fixes regarding file encoding