Update: buildout docs

[svx]

Currently we have under http://docs.plone.org/old-reference-manuals/buildout/ some docs about buildout, these docs are outdated.

• we should update them
• we should add missing stuff
• we should find a new place old-reference-manuals will be not included in the docs for Plone 5

[jensens]

the problem is, that the original zc.buildout documentation was and is complete crap, so we did our own. You can not point people to http://www.buildout.org/en/latest/ and also the doctest style pseudo documentation at https://pypi.python.org/pypi/zc.buildout/2.4.0 is even for hardcore pythonistas difficult to read.

so we should update this old home-grown manual.

[svx]

It is gone in the 5 docs, but still in the 4 docs is that still needed in 5/5.x ?