Prefix the retry limit property name with core_workload.

[core] Incorporate CR Feedback

Prefix the retry limit property with "core_workload".

The default behavior is NO RETRY, which is the current behavior.

But optionally user can enable retry if they are working with a DB backend that is better tolerated by allowing a few retries.

- Move the doc (code comment) to workload_template
- Minor changes in propery parsing logic and log to System.Err;

[core] Incoporate CR comment

Missed one comment before.

1. Use LinkedList rather than ArrayList for the measurement array in RAW. Update size estimation in documentation in workload_template.

2. Add a new composite measurement type which combines HdrHistogram and RAW.

3. Allow user to optionally disable output of summary stats from the raw measurement class.

Raw datapoint output is quite useful and important for two reasons:
 1) Allows the user to do more thorough statistical analysis on the complete set of the data.
 2) Using timestamps that are logged with raw data points, it becomes much easier to investigate and correlate latency outliers at the backend service.

a single file. It shows the defaults and explains usage.