Hi, 

I am currently evaluating exception aggregation tools and so far bugsnag seems to be the most promising for my needs. Especially with a logback extension, which is why I am following your pull request. 

Here at this line you might consider making the initialization of the ```UncaughtExceptionHandler```, which is implicitly done through the constructor, configurable.

In my use-case for example I am running a centralised logging server which is reading log events from sockets and writing them to files as well as to an exception aggregation tool. In this context a global exception handler may not be wanted/needed.