- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

s/ is is / is /g
s/ a a / a /g

Approved by: cperciva
MFC after: 3 days

- Move jenkins.h to jenkins_hash.c
- Provide missing function that can do hashing of arbitrary sized buffer.
- Refetch lookup3.c and do only minimal edits to it, so that diff between
our jenkins_hash.c and lookup3.c is minimal.
- Add declarations for jenkins_hash(), jenkins_hash32() to sys/hash.h.
- Document these functions in hash(9)

Obtained from: http://burtleburtle.net/bob/c/lookup3.c

Fix typos - remove duplicate "is".

PR: docs/154934
Submitted by: Eitan Adler <lists at eitanadler.com>
MFC after: 3 days

add explanatory header license

move jenkins hash to its own header in libkern