RuntimeFramework
RuntimeFramework represents a particular version
            of a common language runtime implementation.
            
                
DefaultVersion is an empty Version, used to indicate that
            NUnit should select the CLR version to use for the test.
            
Static method to return a RuntimeFramework object
            for the framework that is currently in use.
            
Return true if any CLR version may be used in
            matching this RuntimeFramework object.
            
The CLR version for this runtime framework
            
Returns the Display name for this framework
            
The framework version for this runtime framework
            
The type of this runtime framework
            
Construct from a runtime type and version. If the version has
            two parts, it is taken as a framework version. If it has three
            or more, it is taken as a CLR version. In either case, the other
            version is deduced based on the runtime type and provided version.
            
Parses a string representing a RuntimeFramework.
            The string may be just a RuntimeType name or just
            a Version or a hyphenated RuntimeType-Version or
            a Version prefixed by 'versionString'.
            
Returns true if the current framework matches the
            one supplied as an argument. Two frameworks match
            if their runtime types are the same or either one
            is RuntimeType.Any and all specified version components
            are equal. Negative (i.e. unspecified) version
            components are ignored.