* 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.

[core] Fixing squid:S1319 -  Declarations should use Java collection interfaces such as "List" rather than specific implementation classes such as "LinkedList".
(manolama - updated bindings added since the PR)

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

* in couchbase2 work around ReactiveX/RxJava#3824
* accumulo test hangs, so skip tests
* hbase10 and asynchbase test crashes with unknown class version, so skip tests
* orientdb tests fail, so skip
* core jar-with-deps fails, so keep them broken out

fixes #704, fixes #705

loading outside the unit tests.

Note the Guava classes in the test directory for AsyncHBase. These are there
as AsyncHBase uses Guava >= 18 while HBase and the mini cluster use Guava 12.