Bug reports, feature requests or code contributions are always very welcome. To make things easier, here are a few tips:

Reporting bugs, requesting features

Best way to report bugs and request new features is to use GitHub Issues, but you can contact the team also any other way — see the README for details.

Code contribution

Best way to contribute is using GitHub Pull Requests — fork the repository and make a pull request from a feature branch. You can also send patches via e-mail or contact the team in any other way — see the README for details.
Follow the project coding guidelines. In short — try to match style of the surrounding code and avoid any trailing whitespace. When in doubt, consult Coding Style guidelines.
There's a Developers Guide providing step-by-step checklists for almost every development aspect. It's not strictly required to follow it to the point, but doing so will save the maintainers a lot of time during review and merging.
All your code will be released under the project license (see the COPYING file for details), so make sure you and your collaborators (or employers) have no problems with it.