Create a distfiles directory
allow STABLE to work for GUI upgrades

(cherry picked from commit 297825739bbaa138ffd8e20c4c3a53b094a2376f)
Fix installer logging/error reporting.

Due to the GUI using stderr to show upgrade failures we have problems
if we output "set -x" output from the install scripts and other
verbosity to stderr.

Instead use a bounce script to put the stderr of the old install_worker
into a temp file and have the install script use file descriptor

This allows us to debug the installer when it goes upside down, but
also preserve the old behavior and have it be less chatty.
Cache plugin remote fetch for the install dialog

Merge:	releng/9.1.0
Simplify pkg rquery to make the work in one pass

This should reduce a lot of overhead and make jail creation faster.

Ticket:	#2457
Merge:	releng/9.1.0
Sort correctly to remove duplicates

Ticket:	#2457
Merge:	releng/9.1.0
Redirect output of jail start to /dev/null for now

It may cause jail start issues and zombie process due to tty.

Merge:	releng/9.1.0
In the install script, check for these kernel environment variables:
  test.nfs_mount
  test.script
  test.run_tests_on_boot

If they exist, this will allow you to either run
tests as soon as the system comes up, or
add a menu option in the install menu to run tests.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	nanobsd/Installer/bin/install_worker.sh