make better use of the free page at the beginning

[hholzgra]

The 2nd page is not really used so far, it is just empty space to have the overview page on the right hand side for better viewing experience.

The 2nd page could actually be put to a better use though by putting some extra information to it, like a short table of contents to e.g. see where the index pages start, and a list of rendering settings similar to what we display on maposmatic list and detail pages.

[hholzgra]

As doing layouts in raw Pango/Cairo is rather hard I plan to try the rudimentary "HTML to Cairo" renderer found here: https://github.com/gooofy/robinson

[hholzgra]

First experiment looks promising ...