Thanks to Travis CI and the unit tests, the master branch is almost
always of sufficient quality to be used.
Other pros:
* Wiki content matches the default branch.
* Project stats at Github are up to date.
* Less merge overhead at release time.
Summarizing:
1. Separate subject from body with a blank line
2. Limit the subject line to 50 characters
3. Capitalize the subject line
4. Do not end the subject line with a period
5. Use the imperative mood in the subject line
6. Wrap the body at 72 characters
7. Use the body to explain what and why vs. how
The trigger is that pylint doesn't support Python 3.2 anymore, and in
that case Travis CI should not run pylint.
This script takes an optional argument for the executable name of the
corresponding Python version (typically just 'python2' and 'python3').
When not given, 'python' is just run, whatever is in your $PATH. The
latter mode is used in Travis CI.