Adding brief docmarks to all classes

Signed-off-by: Frank Mertens <frank@cyblogic.de>
More docmarks, added Doxyfile

Signed-off-by: Frank Mertens <frank@cyblogic.de>
More docmarks, improved Doxyfile

Signed-off-by: Frank Mertens <frank@cyblogic.de>
Merge remote-tracking branch 'origin/documentation-wip'