I forgot to actually set a context for this change so here. 
Currently I am working on understanding the impact of different workloads using different configuration setups. The Spark Shell is a pretty convenient tool to do so in a Development/Lab environment.

I added those flags to _"quickly"_ understand and assert the behavior of the cluster with a specific workload using different configurations. In most cases _"normal"_ users shouldn't fiddle around the settings, e.g. change from `mesos-fine` to `mesos-coarse`, unless they want to test such effects of the workloads.

In the end, I  see the Spark Shell as a REPL that should aid on the development of Spark Applications. In my mind it should be flexible and allow users to play around with different setups so they can hone in on the setup their Spark Applications should have. I might have gone overboard on setting the local-dir as a shell option but in my case I am deployed in EC2 and want to understand the impact of using a normal EBS vs a HIOPs EBS vs local storage etc. Same goes with other optional arguments added.

Please don't forget that pull-requests that are "enhancements" are basically suggestions. I can remove those arguments that do not make sense for others or place a -X prefix, similar to what the JVM has and hide them from the normal help message.