Completely fixes#1557 and the underlying Doxygen changes that caused
it. Should make fish docs simpler and more robust, more consistent and
generally prettier.
todo:
- trap unmarked text as arguments in context
- test & fix sed portability - see in particular. (so far tested on BSD
(Mac) and GNU sed).
- test Makefile changes
- last round of aesthetic changes and getting that ascii fish in there…
Rework for Doxygen >1.8. Moved large parts of the documentation to a
simplified format, making use of Markdown enhancements and fixing bad
long options.
