[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>

[riak] Moved the utility function createResultHashMap() to the utility class RiakUtils.java.
[riak] Added riak.strong_consistent_scans_bucket_type property to riak.properties file to set the fake bucket-type name.
[riak] Updated README.md with a guide on how to allow strong-consistent scan transactions.

[riak] R, W, etc. options are ignored for strong-consistent updates. So, it's useless to specify them.
[riak] Updated README.md with new considerations about benchmarks which use strong consistency model.

[riak] Configured RiakKVClientTest.java to work with default bucket-type instead of creating a new one.

[riak] Added RiakKVClientTest.java

[riak] Added test unit.
[riak] Set eventual consistency as default in both README.md and riak.properties file, as strong consistency it's not the main model adopted by the db (check http://docs.basho.com/riak/kv/2.1.4/developing/app-guide/strong-consistency/ for further info).
[riak] Fixed getFields() function by transforming it into createResultHashMap(). This function creates the HashMap to give as result appropriately.
[riak] Removed scan transaction support for strong consistency model. 2i search is not allowed for this model, neither there is a suitable search mean to use to achieve a proper scan transaction.
[riak] Done minor fixes to code and comments.

[riak] Done some code/comments cleanup.

[riak] Removed test unit as it only works with a local cluster installation (there is no Riak test or mock utility).
[riak] Packaged into com.yahoo.ycsb.db.riak.
[riak] Removed unused dependencies.
[riak] Bugfix for update() function that returned positive even with no nodes in the cluster.

The binding is based on the one created by Basho Technologies (available at https://github.com/basho-labs/YCSB/tree/master/riak).
[riak] Made compatible with the latest YCSB version.
[riak] Added strong consistency test support and made it default.
[riak] Added missing results return based on provided fields in scan/read functions.
[riak] Added TIME_OUT status return code for those transactions which take too long to complete.
[riak] Added flexible test parameter specification via customizable configuration file and command line options support.
[riak] Added test unit.
[riak] Removed unused Constants.java file.
[riak] Removed many unused function in the RiakUtils.java file.
[riak] Choosed to use executeAsync methods to resolve a bug that didn't allow the benchmark to end whenever one or more nodes of the cluster are killed.
[riak] Fixed license issues in all files.
[riak] Done some refinements to the code.

Added new binding for Riak, based on the one created by Basho Technologies (available at https://github.com/basho-labs/YCSB/tree/master/riak).

Change made to the original version:

- Made compatible with the latest YCSB version.
- Removed unused Constants.java file.
- Added strong consistency test support.
- Done some refinements to the code.
- Removed many unused function in the RiakUtils.java file.
- Choosed to use executeAsync methods to resolve a bug that didn't allow the benchmark to end whenever one or more nodes of the cluster are killed.
- Added TIME_OUT status return code.

To do:
- Add different LOG errors (i.e. insufficient_vnodes_available, ring_not_ready, etc.) - for references, check page http://docs.basho.com/riak/latest/ops/running/recovery/errors/#Errors-and-Messages
- ...