TonY uses both tony.history.location and tony.historyFolder

[erwa]

Currently, tony-default.xml contains tony.history.location whereas other places use tony.historyFolder. We should standardize on one. Looking at Hadoop configs, seems like all.lowercase.period.separated is the more standard naming convention, rather than using camelCase in config names.

We should also avoid hardcoding tony.historyFolder in multiple places and instead define a String constant once and use that elsewhere.

[erwa]

Note that TONY_HISTORY_LOCATION is already defined in TonyConfigurationKeys.java.

[pdtran3k6]

Note that TONY_HISTORY_LOCATION is already defined in TonyConfigurationKeys.java.

For TonyClient, retrieving this value is easy. However, for tony-history-server, although I know that there's prolly a way to import TonyConfigurationKeys.java and use it within the controllers code, I don't know how, so I'm going to work on #97 first, and hardcode the key (tony.history.location + default value) for now (at least inside tony history server code).