Based on today's discussion I've updated PR #291 for CDI-30 (and probably CDI-103)

One thing to note.  Originally I was going to put new methods on Context.  This didn't make sense, as Context was clearly something bound to the underlying thread which we had discussed didn't make much sense and preferable to decouple these.  As a result I created a new ActiveContext object.

So please, comments welcome.

John