Removed patch kit headers. Updated manual page with information from

Removed patch kit headers.  Updated manual page with information from
NetBSD, but changed it to use FreeBSD pathnames, also did not include
the -k option since this version of config does not have it.
Added the at address to the config line so you can specify what address
to link the kernel for:

config "386bsd" at 0xFE000000 root on wd0 swap on wd0 and sd0