Fix Jobs.list in teraslice-client-js and remove jobs method

[godber]

Jobs.list shouldn't return executions:

https://github.com/terascope/teraslice/blob/v0.43.0/packages/teraslice-client-js/lib/jobs.js#L30-L33

and the jobs() method should be removed:

https://github.com/terascope/teraslice/blob/v0.43.0/packages/teraslice-client-js/lib/jobs.js#L35-L38

Earl should be updated to use .list() after this is fixed and we should look to see if we're using Jobs.list() and see if we're really expecting exes somewhere.