asfdata does not support nested data items

[sebbASF]

asfdata needs to return data in a form suitable for use by ezt, which only supports nested entries as attributes.

Items that are dicts need to be converted into a class with entries as attributes.

So a.b['c'] (not supported by ezt) can be accessed as a.b.c (which is).

[sebbASF]

It looks like one could use SimpleNameSpace for this