tidy up namespace indentation

[ichthyo]

Namespaces should either be not indented at all, or be indented in a simple way to support readability. Contrary to this, the existing code is indented according to the behaviour of the "astyle" utility,
because initially a lot of boilerplate code was generated from UML.

Ichthyo meanwhile thinks that some judicious use of indentation actually improves readability, while fine grained indentation slavishly following the number of namespaces tends to get into the way. Thus, when doing this cleanup, within Proc-Layer the goal should be

• to indent anything within any namespaces by one indentation step (2 spaces)
• to indent a private/implementation namespace by two steps

Possibly, this should be combined with the namespace cleanup #162

[ichthyo]

doing that already on occasion since some time

[ichthyo]

pushing to future (and re-indenting on occasion)