[PATCH] doc: changes so each libaray is an appendix

[Bill Spitzak]

This splits the libwayland-client and -server into different
html pages, as they have different objects such as wl_display
with the same name. Also changes so it is easier to add doxygen
output for a new library such as libinput or libweston.

This is far from perfect. In particular the intro text for the libraries is 
the same for all of them. Need to fix it so this text can be read per-library. 
Also I think the links will need a suffix added to them to make them 
per-library as publican does cross-page linking.