When there are overlapping IP prefixes and one disappears,
neighbors associated with it was removed even if there
is another covering IP prefix.

Also fixes some minor bugs in include.

Thanks Kelly Cochran for suggestion and draft patch.

Conflicts:

	nest/config.Y
	nest/rt-table.c
	proto/bgp/bgp.c

Adding some files that was accidentally removed
(instead of moved) in cleanup part 2.

Just one more renaming, old krt_set_notify() to krt_replace_rte().

Remove support for historic Linux kernels,
merge krt-iface, krt-set and krt-scan stub headers.

OS-dependent functions renamed to be more consistent,
prepared to merge krt-set and krt-scan headers.

Name changes:

struct krt_if_params -> struct kif_params
struct krt_if_status -> struct kif_status
struct krt_set/scan_params -> struct krt_params
struct krt_set/scan_status -> struct krt_status

krt_if_params_same -> kif_sys_reconfigure
krt_if_copy_params -> kif_sys_copy_config
krt_set/scan_params_same -> krt_sys_reconfigure
krt_set/scan_copy_params -> krt_sys_copy_config

krt_if_scan -> kif_do_scan
krt_set_notify -> krt_do_notify
krt_scan_fire -> krt_do_scan

krt_if_ -> kif_sys_
krt_scan_ -> krt_sys_
krt_set_ -> krt_sys_

And also fixes some minor bugs in limits.