Refactored new FrameworkVersions to support defaults.
Include TargetFrameworkVersion/Profile in both project and configuration.

This is required to work around MonoDevelop/Xamarin.
Merge pull request #3 from hach-que/JoschaMetze-master

Enable FrameworkVersion and allow Nuget packages without references
Merge pull request #1 from hach-que/master

Reintegrate updates into fork