Add missing copyright notice.
Use direct custom implementations instead of g_handleattr() for CFI and NAND
d_getattr().  Since these drivers use disk(9) KPI and not directly GEOM, use
of that function means KPI layering violation, causing extra g_io_deliver()
call for the request.
Add new script to run release builds.  The script is heavily based upon
the release/generate-release.sh script by nwhitehorn.

This script can use optional configuration file to override defaults,
making running multiple serialzied builds with different specific
configurations or architecture-specific tunings quite easy.

Sample overrideable options are included in the release.conf.sample
file.

Approved by:	kib (mentor)
MFC After:	2 weeks
X-MFC-To:	stable/9 only