Properly handle DOS line endings for WIndows files (no functional change)

Tell git that *.ps1 files are Windows files and should be treated as such.
build-winpe: allow passing in where image and scratch files should be put
build-winpe: adapt to ADK 8.1

Based on https://github.com/nanliu/razor-server/tree/win2012
build-winpe: pass the Razor server URL in at build time

Since there is no way to set the URL of hte Razor server at boot time, we
pass it in at build time as a command line argument to the
build-razor-winpe script
Installer for Windows 2012 R2

Fixes https://tickets.puppetlabs.com/browse/RAZOR-353
* build-winpe/razor-client.ps1: retry contacting to the Razor server

Sometimes, at least on my network, the first few attempts at accessing
/svc/nodeid fail, presumably because the network isn't fully up yet. To
mitigate that, try to contact the Razor server up to 10 times, with 3s
pause in between.