Added a Heap-Slack parameter

This adds the option for users to define a fraction of the container memory that is not used for the JVM heap.

Also, some named parameters were moved out of being inner classes.
adding missing files
Fixing cast typo
Merge pull request #903 from Microsoft-CISL/weimer_jvm_slack

Added a Heap-Slack parameter
Merge remote-tracking branch 'origin/master' into shravan_groupcomm_interfaces
Making parser compatible with new data

Also made doubles into floats
Merge branch 'shravan_groupcomm_interfaces' of https://github.com/Microsoft-CISL/REEF into shravan_groupcomm_interfaces