More detailed UnknownScopeException method

Added a more detailed exception when an UnknownScopeException is thrown.

It is very hard to find out what injection request is failing due to an UnknownScopeException.

These changes use the ExceptionFormatter pattern (from Ninject) to do the same within NamedScope extension.

I've just noticed the line endings are wrong (way too many changes) but am unsure exactly how to resolve this at the moment.