As zabbix agentd cannot run in foreground mode wrap it in simple foreground
application which sends singals whenever it is requested to be killed.

Instantiation shall depend on minimal tools, like system administrator would.

Superseded by buildout:allow-hosts, was not functional anyway.

Most of required eggs are anyway available on pypi, which is much more
reliable than all scattered sources. Idea by Leonardo.

lxml web site, provided by index, is not functional for long time (weeks).
As it is possible to install it directly form pypi (which has a bit of
mirroring) force such way and do not query source website.

The master branch should contains always stable code, so it is required
to define stable version numbers for everything.