Also removed the lib-dir merging with sysdep. Updated #include's
accordingly.
Fixed make doc on recent Debian together with moving generated doc into
objdir.
Moved Makefile.in into root dir
Retired all.o and birdlib.a
Linking the final binaries directly from all the .o files.
Everything is controlled by Doc files in source directories (see the
corresponding programmer's manual entry for the format and look
at Doc and lib/Doc for an example).
Currently it generates HTML indices and calls kernel-doc to generate
per-section HTML files.