[kudu] Update Kudu binding to 0.9.0

Shell scripts to run YCSB.

Add batching in insertion in JDBC client bindings

Fix a typo in Histogram generator

[mongodb] return OK on updates with w=0

Development of RADOS binding of Ceph FS

[mongodb] added logback.xml to mongodb module

[Release] Update top level README.md file to point to 0.9.0 release.

[elasticsearch] Bump version to 2.3.2

This commit bumps the version of the Elasticsearch dependency for the
Elasticsearch binding to version 2.3.2.

[couchbase2] Better Defaults & Scan Refactor

[riak] Added a workaround to allow strong-consistent scan transactions.

[bigtable] Bigtable uses 1ms granularity.

Fixes #733

[core] Add the Utils.getGCTotalTime() method for showing how long

collector. This will allow greater insight into the generations.
Now the client will emmit the stats for each collector at the end of
run along with the totals.

the JVM spent in GC. It now prints the time and percent of time in
the final output.
Also fix cases where the garbage collector implementation returns
-1 if the count or time isn't implemented.

[core] add operation tracing via Apache HTrace.