Release candidate 2.3.3.7

This release includes:

* Rename the _Init layer to "rack"
* Decode URLS when reporting them
* Resque layer naming split into 1) client queuing of a job: 'resque-client', 2) Resque worker running a job: 'resque-worker'
* Fix for an extension load error and some refactoring of functionality into a base module (OboeBase)
* Improved and more resilient method profiling
* Further refactoring for Ruby 2.0 support
* Track the version of the instrumentation installed