Replace NonStrict with NonStrictExpectations
Fix documentation
Avoid recreating the same auth string over and over again
Do not display the name as it's null
Use Raven.RAVEN_THREAD to determine if the thread is managed by Raven

Instead of using guards, ensure that the current thread is set as managed
by raven.
This allows to get rid of synchronisations and maximise the throughput
PMD notices the potential problems of using ThreadGroup, in this case it's fine
Do not rely on the default charset, force everything to UTF-8
DateFormat is flaky when used in a multithreaded context

Use a new instance each time instead
Add comments on RAVEN_THREAD usage
ExceptionWithStackTrace doesn't require to be bound to the surounding class