[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.

[scripts] Fix bin/ycsb for Python 2.6 and bin/ycsb check_output

[geode] Update geode binding for v1.0.0-incubating.M2

[elasticsearch] Return not found instead of error

[core] Add the "measurement.trackjvm" property to measure JVM statistics

[core] Parallel run and string sort order

Conflicts:
	core/src/main/java/com/yahoo/ycsb/workloads/CoreWorkload.java

fixed conflict, fixed extra spaces and space between methods

[kudu] Upgrade client dependency to Kudu 0.8.0

[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.

This commit modifies the Elasticsearch client to return Status.NOT_FOUND
when an operation fails because the document requested does not
exist. This modifies the previous behavior which would return
Status.ERROR in this case.

This commit also moves the statements that would return Status.ERROR
into the corresponding catch blocks so that it is clear that
Status.ERROR is only being returned on error paths.

Kudu 0.8.0 deprecated how predicates were specified and introduced
a more simple one.

when the status thread is enabled. This tracks the GC count, thread count,
memory used and average system load (if implemented) over time as well as
the max and min for each measurement at the end.
Also, every run will now measure the total number of garbage collections
from all pools.

[googledatastore] Update googledatastore API version to v1beta3.

[asynchbase] Fix Netty library version issue that prevents it from

loading outside the unit tests.

[asynchbase] Add AsyncHBase as an alternative to the default HBase cl…

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.

[core] Add an incrementing printable string generator.

This will be used for #653 for databases that require keys or other values to use a limited character set. This generator will create a sequence of strings using a defined list of UTF code points from which to pull.

Fixed nits suggested by @busbey

[riak] Added new binding for Riak, based on the one created by Basho Technol…

[core] Add CoreWorkload.createOperationGenerator() for use in other w…

[couchbase2] Allow to log latency & runtime metrics.

[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.