Updated code to satisfy the checkstyle validation.

Fixes #365

In order to get the tests to pass again, reverted MongoDbClient to use update with upsert instead of insert when batch size is 1.

Added journal=true back into MongoDB connection string.  For now, the connection string will contain both "j" and "journal", until such time as the MongoDB Java driver supports "journal".

Simplified insert CRUD code to always use insertMany even when batchSize == 1,
 as there is no performance penalty for this in the driver.

Changed visibility of static field from protected to private in final OptionsSupport class for MongoDB.

Changes:
1. mongodb configuration parameter bug (mongodb.url)
2. README file change
3. Some cleanup. Default DB is 'ycsb'

1. mongodb configuration parameter bug (mongodb.url)
2. README file change
3. Some cleanup. Default DB is 'ycsb'

MongoDB 3.0 driver.

Created tests for the basic DB operations.

Updated MongoDB Inc. Driver version to 3.0.2.

to the 3.0 driver from MongoDB Inc. and updated to the new Document and
fluent APIs.

URI to configure the client. Old properties are deprecated and but will
be added to the URI if present and the URI does not already contain a
value for the setting.

When running workloads that use the "insert" operation, we get a lot of
duplicate key exceptions from the server. Changing to upsert to avoid
these exceptions.

No need to call getError on writeResult. any errors for writeConcern level will throw exceptions and be caught in catch block

each test client.

Add a control (via properties) for the number of connections the Mongo
instance will create/use.