oll-doc: Make summary lists more generic

The lists that are used to display the summary of used
categories and tags are now generated from within the
Snippets object. This will make it possible to use that
inside the application window too (independently how it will
be used on the long run).
oll-doc: show maximized initially
oll-doc: Create nicer UI (display in-app)

Display the parse results in the main window
oll-doc: Make output correctly sorted

There had already been the sorted lists available,
it's just one should make use of them ...