- 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

Mdoc Janitor:

* Use 'manual' instead of 'man' for consistency.

ispell sweep of share/man/man9/*.

mdoc(7) police: markup, grammar and spelling nits.

Reviewed by: davidc

Add manpages describing various vfs and vm APIs.

Submitted by: Chad David <davidc@acns.ab.ca>