CMake Nightly Date Stamp
VS: Add support for .NET target framework version

Teach CMake to generate the TargetFrameworkVersion XML node as
documented at

 http://msdn.microsoft.com/en-us/library/vstudio/ff770576.aspx

from target property VS_DOTNET_TARGET_FRAMEWORK_VERSION.
Merge topic 'vs-TargetFrameworkVersion' into next

cfe6300 VS: Add support for .NET target framework version
82771f1 CMake Nightly Date Stamp