When a protocol was enabled interactively (but disabled in the config
file), then reconfigure in some cases forgets to disable it.

If show route cmd was used with a filter that changed preference,
BIRD crashed.

Adds option -u and -g to specify user and group.
When different user (than root) is specified,
linux capabilities CAP_NET_* are kept.

 - Fixes several conflicts in the grammar.
 - Fixes a bug in (a..b, c) pair patterns.
 - Makes pair patterns orthogonal.
 - Allows term expressions in pair patterns without additional ( ).
 - Allows several comma separated values in switch cases.

Adds option 'med metric' allows to compare MEDs
between routes received from different neighbors.

When buffer is too small (because of change between sysctls()),
needed is *not* changed.

(and minor changes in documentation)

Sending malformed network prefixes in LSAs causes OSPF to crash
just after the LSA is propagated to the other routers.

Mainly changes IA_UNNUMBERED to IA_PEER and adds IA_HOST. Also do not
show broadcast addr in show interfaces. Nobody cares for that.