- 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

The NetBSD Foundation has granted permission to remove clause 3 and 4 from
their software.

Obtained from: NetBSD

Merge changes to the NetBSD copyright (advertising clause removal).

Sync libedit with recent NetBSD developments. Including improvements to the
vi-mode, removal of clause 3, cleanups and the export of the tokenization
functions.

Not included: config.h, filecomplete.{c,h}