Also fix a few README formatting issues.

        mvn org.apache.rat:apache-rat-plugin:0.11:check -D rat.numUnapprovedLicenses=5000

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.

Replaces numeric status codes with a canonical set of Status objects,
each with a short name and description.
Bindings with more specific errors (e.g., timeouts) return additional
statuses.

This changes the default output from messages like:

   [UPDATE], Return=0, 511

To:

   [UPDATE], Return=OK, 511

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.

In OneMeasurementHdrHistogram, now reading hdrhistogram.percentiles
from workload configuration. This property is a comma delimited string
of Integers to use as percentile values.

This implements #437

size for the window so a mask can be used instead of a modulo operation.
This avoids issues when there is overflow of the id integer values to
negative values.

The HdrHistogramReader makes some problematic assumptions on the roles
played by start time, base time and histogram start/end times. This is
to be revisited in a future release of HdrHistogram (see
https://github.com/HdrHistogram/HdrHistogram/issues/69). In the meantime
this change will make YCSB record as expected by the reader:
a. Set histogram log base time (same as start time)
b. Only create the recorder after the log has been setup

final, refactor repeated export code from subclasses.

closes #239.

Origin patch in PR-286.

client (worker) thread completing via a CountDownLatch.

Fixes #316

(trailing whitespaces, 2 spaces instead of tabs and e.t.c)

* returncodes -> OneMeasurement
* HashMap -> ConcurrentHashMap

Closes gh-353

As a part of branching to stage 0.2.0 release in #266, set version
for continued development on master branch.