iproute2 add hoplimit parsing and update usage and documentation

iproute2 add hoplimit parsing and update usage and documentation

- Parse and handle the hoplimit ip route option and add it to the usage
  line and documentation.

- Add the missing reordering ip route option to the usage line.

- Add documentation for initcwnd ip route option.

Tested by setting hoplimit and retreiving it via "show".

Signed-off-by: Gilad Ben-Yossef <gilad@codefidence.com>
[ported to HEAD, fixed a bug with hoplimit lock handling, added documentation]
Signed-off-by: Ori Finkelman <ori@comsleep.com>
Signed-off-by: Yony Amit <yony@comsleep.com>