Expose the job's socket directory with a single configuration option about bpm-release

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/161028730

The labels on this github issue will be updated when the story is started.

[xoebus]

I'd like to make a 0.13.0 release but would like to make sure that this has at least been considered before that point.

[jfmyers9]

I don't mind adding something similar, I just personally feel like sockets: is just one of many use cases for using /var/vcap/sys/run. Haven't been able to come up with a better name yet, still thinking on it.

[xoebus]

Not important enough.