- 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

Remove XMODEM_DL support. It never was complete and only serves to
increase the diffs with other arm boot2 loaders.

MFp4:
Add support for the CENTIPAD board (http://www.harerod.de/centipad/index.html)
(which is a very cool, very small ARM board)
Add support for KB9202B (it has different memory)
Make BOOT_FLAVOR settable
Minor cleanup nits

Approved by: re@