[Hipsec] new HIP draft versions

[Tom Henderson <[e-mail]>]

All, the changes in draft version 18 are below:

    o  Update ORCHID reference to newly published RFC 7343

    o  Update example checksum section to RFC 7343 HIT prefix of
       2001:20::/28, and fix incorrect Header Length fields

    o  Update IANA considerations comment on legacy HIP_TRANSFORM
       parameter naming

    o  Add 2048-bit MODP DHE group as Group ID value 11.

I realized immediately after publishing version 18 (upon revisiting the 
tracker) that I hadn't updated the typo in the IPv6 documentation prefix 
in Appendix C, so I created draft version 19 for this.  While doing so, 
I discovered that the reference to the IPv4 documentation prefix was 
wrong, so I fixed this.  Finally, I reviewed Appendix E, Section 3.2, 
and RFC 7343 (per Francis Dupont's comment) and made a small change to 
Appendix E that I hope resolves the comment.

    o  Correct documentation prefix in Appendix C from 2001:D88/32 to
       2001:DB8/32, and update IPv6 checksum

    o  Correct documentation prefix reference from RFC 5747 to 5737

    o  Clarified HIT generation in Appendix E

To my knowledge, these updates close all previously raised issues on the 
draft.  It may be worthwhile for another implementation team to confirm 
the new checksum values that I generated for Appendix C.  I do have a 
question about the HIT Suite IDs that I'll post in another message.

- Tom