Release v0.12.4.
This is a small bugfix release. Changes since v0.12.3:
- Packaging fixes for Debian.
- Support for Python 2.6 has officially been dropped (it had already
bitrotted, so now a nicer error message is shown straight away). - Bug in local_bind for ping commands fixed.
- More graphs for tcp_* tests and fixed labels on HTTP test graphs.
- Catch unhandled exception that caused crashed when using a null output
formatter.