[Zope-CMF] GenericSetup dependency support

[Wichert Akkerman]

I did some work on a wichert-dependencies branch for GenericSetup today.
It works quite simple: runAllImportStepsFromProfile will now look for
required contexts in the profile metadata. Any found dependencies will
be imported before the current code is imported. There is a new option
ignore_dependencies which can be used to disable this behaviour.

I would appreciate some more eyes on these changes before merging this.

Wichert.

-- 
Wichert Akkerman <wichert at wiggy.net>    It is simple to make things.
http://www.wiggy.net/                   It is hard to make things simple.