Make Windows Build Machine from public URLs (step 3)

Put  8.0 signtool in the path
Install  WinDDK 7.1 from public ISO
Install 7zip and download WinDDK 7.1 public ISO
Allow Win8SDK to download sdksetup.exe
Use public URL for SDKWin8
Change WDKWin8 URL into two public URLs
Remove MSM URL and step
Delete install-msms.ps1
Make install-wdk-win8.ps1 download exe and msi
Merge pull request #14 from stefanopanella/master

Make Windows Build Machine from public URLs (step 3)