Prevent Sysprep from killing Provisioning

Force Sysprep to quit after completion, rather than reboot or shutdown

This will hopefully prevent any issues with race conditions in the
provisioning cycle.
Clarify 8.1 Answer file descriptions

Clarify 'C:\' drive name and add more descriptions to the various
first-run commands.
Remove cache clearing

Disable the removal of the cache.
Log files are currently useful, and might be necessary in the future for
further setup troubleshooting.