Revert "Retarget to .net 4".

Targeting 4.0 breaks package restore due to nuget limitation. 4.5 it is!
http://nuget.codeplex.com/workitem/3135

This reverts commit 37e54aaa4145f888bf95e891e2d3e567159f58b8.

Conflicts:
	MSI/Product.wxs
Fix up installer for 64-bit
Add all components for a working installer!