Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC revisions 230804,254265,255908,256338,256345,256347-256348,256489,
257842-257845,257872,259115,259143,259276,259468-259469,259572,259686,
260260-260262,260866, and 260900 (25 revisions; summarized below)...
r230804: Fix a whitespace nit (kevlo)
r254265: (recording mergeinfo only)
r255908: Remove the is (Iceland) mirror per mail from the admins (brd)
r256338: Dump 4096 bytes from /dev/random to /entropy (des)
r256345: Rewrite the keymap module
r256347: Detect when an interface is wireless (Warren Block)
r256348: Merge dumpdev into regular services; enable (Allan Jude)
r256489: Add executable bit to docsinstall and entropy scripts
r257842: Performance and debugging enhancements
r257843: Remove ttys(5) munging from previous commit
r257844: Copy install log to deployed /var/log for debugging
r257845: Fixup to last commit
r257872: Doc fixup -- add missing .El (joel)
r259115: Prevent log file from becoming truncated
r259143: Use sed(1) /i instead of /I (eadler)
r259276: Fix `local: Not in a function' error in logfile
r259468: Ignore mouse-release command from VMware
r259469: Mask error from newaliases(1) when hostname not fully qualified
r259572: Fix `rm: /tmp/bsdinstall_etc/fstab: ..." error in logfile
r259686: Move VMware mouse-release solution
r260260: Remove what appears to be a stray debugging printf
r260261: Lower priority of open wireless access policy (gavin)
r260262: Allow bsdinstall to use WPA-Enterprise networks (gavin)
r260866: Fix bad comparison and fix file comment (Christoph Mallon)
r260900: Whitespace and style nits

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Fix mirror selection, which was broken by stderr redirection.

Reported by: Garrett Cooper

Update to reflect net install changes.

Add support for optional distributions, installation of the ports tree and
src. Fitting all of this on a single CD along with a full system requires
changing the default compression algorithm from gzip to xz.

Import bsdinstall. This is meant to be (eventually in conjunction with
pc-sysinstall) a replacement for sysinstall in the 9.0 release and beyond.
Currently supported platforms are sparc64, pc98, i386, amd64, powerpc, and
powerpc64. Integration into the build system will occur in the coming
weeks.

Merging with pc-sysinstall will use this code as a frontend, while
temporarily retaining the interactive partition editor here. This work
will be done in parallel with improvements on this code and release
integration.

Thanks to all who have provided testing and comments!