- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

per style(9):
Kernel include files (i.e. sys/*.h) come first; normally, include
<sys/types.h> OR <sys/param.h>, but not both. <sys/types.h> includes
<sys/cdefs.h>, and it is okay to depend on that.

Add some USB gadget example drivers for USB audio, USB keyboard,
USB mouse and USB modem classes. Hopefully someone will find
these examples useful when implementing USB device side drivers
using the FreeBSD USB stack.