Make Windows Build Machine from public URLs (step 1)

This change is the first result of the effort to install
all tools needed to build OpenXT windows components using
public URLs.

- Update Helper URL
- Remove libre branch tag
- Update Cygwin URL
- Update nsis URL (2.46 now) and Check we are using >= than 2.23
- Update capicom URL
- Add MSMSrc patch
- update dotNetFx45_Full_setup.exe URL
- Update SQLSCE32 and SQLSCE64 URLs
- Update VS2012U4 URL
- Update Wix URL

Wix URL is now hardcoded in install-wix.ps1 (This is needed because
if we put this URL in the config file the XML parser fails because
of the &, so embedding the URL here is a workaround for the problem)
Merge pull request #4 from dickon/master

a README.md for openxt.git which points people at the wiki
Merge pull request #10 from stefanopanella/master

Make Windows Build Machine from public URLs (step 1)
[do_build.sh] Remove optional steps...

... to minimize build breakage.
- nilfvm does nothing.
- copy requires extra configuration lines that are not yet documented, or it tries to copy stuff to /master, which breaks the build for most users.
- extra_pkgs can be replaced by just manually building the extra packages needed, which widely vary between users anyway.
- packages_tree also requires extra configuration. That step is probably not needed for most users either.
Merge pull request #11 from jean-edouard/master

[do_build.sh] Remove optional steps...
Remove Windows Quality Tools step
Adding inf2cat to Win7DDK path
use INF2CAT command from win7DDK path
Use public URL for VS2012P
Use Public URL for VS2102 Premium
Fix VS2012 Pro URL
Default WinDDK is now 7.1
WDK 7.1 signtool.exe lives in a different place
Stop Installing WDK 6001
Remove WDK 6001 installer script
Merge pull request #12 from stefanopanella/master

Make Windows Build Machine from public URLs (step 2)
Give output when the script is done
Merge pull request #13 from dotdashnotdot/master

Give output when the script is done so that if run from a run registry key the user can see something on successful completion.