fixed duration formatting in nunit report
fixed duration formatting in xunit report
fixed culture sensitive output in ConsoleListenerTests
fixed culture sensitive sorting in MethodFilterTests
fixed culture sensitive sorting in ConventionTests
Merge pull request #42 from JonasSamuelsson/false-negatives

fixie.tests reported false negatives for some cultures
Simplify ExceptionInfoTests in preparation for upcoming API change.
AssertionLibraryFitler no longer filters by namespaces, which made it too likely to filter out useful stack trace information.  Instead, it filters by full type names, given types that comprise the assertion library you want to hide.
Rename Convention.AssertionLibrary to Convention.HideExceptionDetails, for readability within conventions.
Update README to document the assertion library filtering feature.
Trivial update to README.md sample code.
Fix typo in README.md