* Factor out starting Ray processes.
* Detect flags through environment variables.
* Return ProcessInfo from start_ray_process.
* Print valgrind errors at exit.
* Test valgrind in travis.
* Some valgrind fixes.
* Undo raylet monitor change.
* Only test plasma store in valgrind.
* Implement Node class and move most of services.py into it.
* Wait for nodes as they are added to the cluster.
* Fix Redis authentication bug.
* Fix bug in client table ordering.
* Address comments.
* Kill raylet before plasma store in test.
* Minor
* Separate out functionality for querying client table and improve cluster.wait_for_nodes() API.
* Linting
* Add back logging statements.
* info -> debug
## What do these changes do?
This PR exposes the CL option for using a config parameter. This is important for certain tests (i.e., FT tests that removing nodes) to run quickly.
Note that this is bad practice and should be replaced with GFLAGS or some equivalent as soon as possible.
#3239 depends on this.
TODO:
- [x] Add documentation to method arguments before merging.
- [x] Add test to verify this works?
## Related issue number
