Avoid dependency hell

The two scenarios below really bother me.
- User writes an observer that has conflicting dependencies with the Fluo worker thats running the observer.
- User writes two observers that have conflicting dependencies with each other. For example one Observer uses LIB A which depends on guava 18 and another Observer uses LIB C which depends on guava 13.

I am thinking it would be nice isolate Observer depenencies from each other and from the Fluo worker framework. OSGI may be a a way to do this, but I am not sure because I know very little about OSGI. I am going to explore using [Apache Felix](https://felix.apache.org) in the worker to accomplish this dependency isolation. Any other suggestions/solutions would be welcome.