- 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

Merged from the following changes.
- sys/dev/fdc/fdc.c revision 1.281
- sys/dev/fdc/fdcvar.h revision 1.3
- sys/dev/fdc/fdc_isa.c revision 1.7

Merged from recent fdc driver changes.
Make a separate function to check FDD type.

- Merged from sys/dev/fdc/fdc.c revision 1.275.
- Break out the cbus front end from fd.c.
- Remove the pccard support because it was broken.