Allow the user to set up its own ExecutorService
Set up a proper Executor for AsyncConnections in DefaultRavenFactory
Fix indentation and imports
Add tests for the AsyncConnection
Remove setCulprit based on an exception

The goal of setCulprit is to determine where the event was captured, not
where it originates from (if it's an exception).
Set the culprit in jul with a fake stackframe
Properly set the culprit in log4j
Fix string comparison using ==
Properly set the culprit in log4j2 and logback
className and methodName should never be null in StackTraceElement
In jul, sourceClassName and sourceMethodName could be null
In a StackTraceElement the class and method are always provided
Add tests for EventBuilder and Event