- *incompatible* Default measurement changed from histogram to hdrhistogram
  Users who want previous behavior can set the 'measurementtype' property to 'histogram'

- *incompatible* Reported 95th and 99th percentile latencies now in microseconds (previously in milliseconds)

Conflicts:
	core/src/main/java/com/yahoo/ycsb/measurements/OneMeasurementHdrHistogram.java

closes #371

[docs] Fixes #393 - Update the curl command to use the --location option

[travis] Fixes #389 - Update .travis.yml to use the container based infrastructure for Travis Builds.

[travis] Fixes #389 - Update .travis.yml to use the container based infrastructure for Travis Builds.

[docs] update README for 0.3.0 release.

Added ASLv2 header to most files missing one.

[core] Fix #380 by working around recorder/logger initialization timing.

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.

[mongodb] Update the pom.xml to make checkstyle fail the build. Fixes #365

Updated code to satisfy the checkstyle validation.

Fixes #365

[mongodb] Update the MongoDB driver version to 3.0.3.

Fix HashMap (gh-353) bug.

Shutdown the status thread as soon as clients complete (Issue #316)

closes #239.

Origin patch in PR-286.

client (worker) thread completing via a CountDownLatch.

Fixes #316

Fixes #344.

In order to get the tests to pass again, reverted MongoDbClient to use update with upsert instead of insert when batch size is 1.

Added journal=true back into MongoDB connection string.  For now, the connection string will contain both "j" and "journal", until such time as the MongoDB Java driver supports "journal".

Simplified insert CRUD code to always use insertMany even when batchSize == 1,
 as there is no performance penalty for this in the driver.

Changed visibility of static field from protected to private in final OptionsSupport class for MongoDB.

[cassandra] change the port of Cassandra (previous version 1.2) as a parameter instead of a constant value such as 9160

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

* returncodes -> OneMeasurement
* HashMap -> ConcurrentHashMap

Closes gh-353