The linux kernel should be able to deal correctly with source-sensitive ipv6
route entries since 3.11 (when it is configured with IPV6_SUBTREES).  This patch
modify the kernel so that ipv6 route entries sent into the kernel are not pushed
in a different routing table.

The behavior for v4 doesn't change.

Since it's a route attribute, it fits better there.

Add 3 new options to configuration and manpages:
src-ip, src-eq, src-le and src-ge.

It also update the route's id.

The field "result" is in fact an additional cost.