Version 1.1

Milestone #19: v1.1, including:
- [x] #16 instance pooling fix
- [x] #17 enqueuing options refactor
  - [x] interface JQJob -> abstract class JQJob
  - [x] JQJobs know their own enqueuing options
  - [x] stop passing options around alongside JQJobs (["data clumps" smell](http://martinfowler.com/bliki/DataClump.html))
- [ ] #20 @todo cleanup
- [ ] document changes

This merges the long-running fork that has existed for some time, with a few extra cleanups and bugfixes here at the end.