- 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

Minor mdoc fixes.

In this GRN, Marcel Moolenaar overhauled the logic for mounting
the root file system on bootup:

|------------------------------------------------------------------------
|r214006 | marcel | 2010-10-17 22:01:53 -0700 (Sun, 17 Oct 2010) | 20 lines
|
| Re-implement the root mount logic using a recursive approach, whereby each
|root file system (starting with devfs and a synthesized configuration) can
|contain directives for mounting another file system as root.
|------------------------------------------------------------------------

This commit adds a mount.conf(8) man page which documents
the root mount logic. mount.conf(8) also provides some examples
for the /.mount.conf file, which can be used to change the root mount behavior.

Reviewed by: marcel bjk