The only functional change is the following:
- before: sys.path begins with [*/product/*/tests] followed by [*/tests]
- after: sys.path begins with [prj1/product/*/tests, prj1/tests,
                               prj2/product/*/tests, prj2/tests,
                               ...]
This should have no impact.

Also remove 2 configuration lines that only repeated the default values

because new bt5 may have been added in the meantime.

It was missing in 3a157be8

It is not used by default.

It mangles buildout:develop as described in https://github.com/fschulze/mr.developer/issues/57,
and buildout:develop is used in many project to checkout and develop various
eggs in "slapos" way.

On Debian-based distributions,  gcc FTBFS because of special  linker files and
architecture-dependent  headers being  available in  /usr/lib/<triplet> rather
than /usr/lib  and /usr/lib64. This avoids  settings respectively LIBRARY_PATH
and CPATH manually on such distributions.

http://kb.askmonty.org/en/mariadb-530-release-notes

zabbix_agentd is  a standalone  daemon which can  be ran  through supervisord,
whereas zabbix_agent is  supposed to be used with inetd,  thus use the former,
likewise zabbix-agent software instanciation profile.

Need to allow from www.owlfish.com, as WSGIUtils is available there.

Added white spaces arround "="

This value could be much higher in future because it is only sleep for so
long after instance be well setupped.