Update cassandra2-cql driver to only run tests on jdk8

[cassandra] properly clear cached containers.

clear containers before we use them rather than after, so that in the case of
exceptions we can recover.

closes #127

[S3] Close opened S3Object

[hbase10] Fix the init() method to properly construct a single…

object. Previously N objects were instantiated because the method didn't
check to see if the connection was null.

[core] Add a UnixEpochTimestampGenerator

[dynamodb] Checkstyle updates for DynamoDB.

[geode] Checkstyle updates for Apache Geode (incubating)

[tarantool] Checkstyle updates for the Tarantool binding.

[infinispan] Checkstyle updates for the Infinispan binding.

[core] Add byte to double and long conversion methods to Utils.

These will be used for #653 to write timestamps and numeric values
to the ByteIterator maps.

Fixes #612.