Elevate the installer only when Net40 is missing

- [x] add a dummy installer to ensure the package elevates correctly
- [x] adjust bootstrapper to run last
- [x] update tests to reflect actual behaviour
- [x] switch out to use the web installer that ships with the WiX tools 
- [x] confirm sample is still broken for vanilla VM due to not applying [KB2468871](http://www.microsoft.com/en-us/download/details.aspx?id=3556)

Resolves #162