Switched to "shark.cache.policy" and added some parsing helpers in CachePolicy.

The policy table property configs are here since I wasn't sure where to comment about them.
It seems like SharkConfVars only deals with session-wide Conf properties. Would it be alright to add a utility that only helps with table properties, something like a "SharkTblPropertyVars" Object? It'd double as a place to document those variables. Probably should be a new JIRA issue/future PR.