Switch Accumulo into multiple modules, one per minor release

[accumulo, accumulo1.6, accumulo1.7, accumulo1.8] switch Accumulo to minor version specific bindings.

* break out accumulo modules
* add deprecation warning
* switch travis to use short hostname to get around long hostname error.

closes #787

* remove mapkeeper and voldemort from command help, since we don't build them
* fix ordering of modules in root pom

closes #328

* [hbase10] Fix #701 by mimicking the same locks from the HBase 0.98 client in the HBase 10 client.

* Address CR comments, thanks @allanbank.

* Addressed the table lock.

* Restore the lock on the connection shutdown.

Also addressed @jasontedor review, thanks!

[core] Change the RemainingFormatter to reflect non-plural times, fix…

NOTE if you parse the standard out of YCSB, you'll be missing the "s" sometimes.

the existing YCSB API to generate time series data (numeric values associated
with timestamps).
See the TimeSeriesWorkload.java class Javadocs for details on how to use it
with a client and workloads/tsworkload_template for parameters.
Also add the BasicTSDB instance for printing/debugging the workloads.

* Google Datastore to use default credentials.

* Google Datastore to skip Index.

* Add oraclejdk9 to .travis.yml

* Upgrade maven-compiler-plugin

* Exclude jdk.tools from hadoop dependency

* Set minimum maven version to 3.1.0+, due to reqs for ES testing
* remove oracle jdk7 per travis-ci/travis-ci#7884
* Skip ES5 cluster spin-up if tests are skipped.
* Increase test heap for asynchbase binding from Travis 2048m to 4096m
  - https://docs.travis-ci.com/user/build-environment-updates/2017-09-06/
* temporarily remove the riak service on travis
  - currently fails w/o details
  - http://docs.basho.com/ fails to load, so I can't spin up a test node locally.

closes #994 

[elasticsearch,elasticsearch5] Add Elasticsearch 5.x binding

This commit removes an extraneous newline from
ElasticsearchRestClient.java.

This commit replaces some magic numbers (HTTP status codes) with
already-existing constants for this purpose.

This commit marks a field intended to be treated as a constant as final.

This commit removes duplicate test code from the elasticsearch5 and
elasticsearch5-rest test classes.

timestamps in a non-repeating random order.
Modify UnixEpochTimestampGenerator so that the random generator can
extend it.

Signed-off-by: Chris Larsen <clarsen@yahoo-inc.com>

the number of unique combinations of tables, keys and fields per
database operation. This is useful for tracking distributions.

Signed-off-by: Chris Larsen <clarsen@yahoo-inc.com>

for passing to db implementations as an abstraction on the byte array itorator.

Signed-off-by: Chris Larsen <clarsen@yahoo-inc.com>

Signed-off-by: Chris Larsen <clarsen@yahoo-inc.com>

The comments were incorrectly referring to ElasticsearchClient but they
should be referring to ElasticsearchRestClient instead.

This commit removes an unrelated POM change for the original
(Elasticsearch 2) binding.

This commit wraps the usage of a content builder in a try-with-resources
block to ensure that it is correctly closed.

This commit changes the name of a property, es.newdb, to es.new_index as
this is more consistent with the terminology used in Elasticsearch.

This commit removes some unnecessary logging statements for the
elasticsearch5 and elasticsearch5-rest bindings.

This commit sets the log of the internal transport client used in the
Elasitcsearch 5 binding to use standard error instead of standard out.

This commit reverts some unrelated changes to POMs for other bindings,
perhaps made inadvertently while merging master into a development
branch.

This commit adds some basic formatting to the transport client logs for
the transport client used in the Elasticsearch 5 binding.

This commit sets the Elasticsearch 5 binding to only use the
elasticsearch-maven-plugin if tests are running on JDK 8.

This commit updates the Elasticsearch 5 binding docs to include
references for starting Elasticsearch 5, how to configure the transport
client, and how to use the low-level REST client binding.

This commit fixes issues with the Elasticsearch 5 transport client and
REST client bindings so that all tests pass.