Make all options work

[bertfrees]

• Options that have been implemented in the generic dtbook-to-pef should not be overwritten.
• Options that were not generic enough to implement in the generic dtbook-to-pef should be implemented here.

I've already fixed $page-width, $page-height and $show-braille-page-numbers in 84e0368 but some other options may be left. Ideally all options, especially the ones implemented here, should be covered by unit tests.