doc: fix texi2html warnings

** Node following `Config Commands' in menu `Common Invocation Options'
and in sectionning `Terminal Mode Commands' differ

** Node following `Terminal Mode Commands' in menu `Config Commands' and
in sectionning `Common Invocation Options' differ

** No node following `Router Advertisement' in menu, but
`Interface-scope RA commands' follows in sectionning
lib: simplify distribute.c's code.

Use loops and variables instead of doing each cases by hand.
Use static functions instead of rewriting code.
ripd: code simplification for redistribution.

Use loops and variables instead of doing each cases by hand.
Use boolean instead of having 2 almost identical functions.
ripngd: code simplification for redistribution.

Use loops and variables instead of doing each cases by hand.
Use boolean instead of having 2 almost identical functions.
remove some unused files and directories

* zebra-guile interface never made it past a prototype
* init/ was an empty directory
* FreeBSD ports didn't use the files from ports/
* mrlg.cgi is available from the Internet (again)
ospf6d: display DN-bit in prefix options

Update ospf6_link_lsa_show() and ospf6_intra_prefix_lsa_show() to decode
all prefix options bits of RFC5340. This doesn't affect any prefix
processing.
ripd: justify memory management for interface auth parameters

Function rip_interface_delete_hook() doesn't need to set pointer to NULL
after XFREE(). Update a few functions in rip_interface.c to use XFREE()
and XSTRDUP() instead of free() and strdup():
* rip_interface_reset()
* ip_rip_authentication_string()
* no_ip_rip_authentication_string()
* ip_rip_authentication_key_chain()
* no_ip_rip_authentication_key_chain()
zebra: justify setup and use of RA/IPv6 macros

Make RTADV mean "actually compile zebra RA code" and depend on both
HAVE_IPV6 ("any IPv6 is requested and available") and HAVE_RTADV ("zebra
RA is requested"). Remove empty conditional copies of
rtadv_config_write() and rtadv_init().
zebra: fix struct rtadv memory type

Add MTYPE_RTADV memory type and use it in rtadv_new() for the allocation
of top-level struct rtadv. There is no deallocating function for the
structure.
zebra: make come rtadv function arguments const

*   rtadv_recv_packet()
*   rtadv_send_packet()
*   rtadv_process_solicit()
*   rtadv_process_packet()
*   rtadv_setsockopt()
*   rtadv_setsockopt_filter()
*   rtadv_prefix_lookup()
*   rtadv_prefix_get()
*   rtadv_dns_lifetime_fits()
*   rtadv_event()
ripd: remove stale comment in rip_response_process()
ospfd: justify size_t printing in ospf_recv_packet()
build: add configure options testing script
zebra: spelling
doc: update process list in basic.texi
lib: make the IPv6 address and prefix parser slightly more strict.

This makes it possible to have both "show babel route A.B.C.D/M"
and "show babel route X:X::X:X/M" commands at the same time without
the parser complaining about ambiguity.
babeld: implement show babel route A.B.C.D/M commands.
babeld: fix missing case in babel_prefix_eq.

This would cause show babel route to ignore IPv4 prefix length.
babeld: implement show babel route ADDR.

This is just an alternate syntax for host routes, but it's
convenient when working with pure meshes.
babeld: include distribute lists info in show running-config.