OGM-471 Don't create associations prior to deletion
OGM-342 Making write concern configurable on a global level via the API
OGM-342 Doc improvements and clean-up
OGM-342 Providing mock client for MongoDB
OGM-342 Introducing object representing a batch insert in order to append additional information such as the write concern to it
OGM-342 Enhancing GridDialect contract to pass additional information to tuple operations and batch operations
OGM-342 Applying write concern given on entity level
OGM-342 Applying write concern setting given on property-level
OGM-342 Providing facility for simplified parameter null checks
OGM-342 Allowing to specify a specific WriteConcern implementation type
OGM-342 Removing redundant tests; Organizing option test packages
OGM-342 Updating reference guide
OGM-342 Providing common interface for TupleContext and AssociationContext
OGM-342 Moving annotation converters into "impl" package
OGM-342 Properly applying write concern when creating associations
OGM-342 Incorporating review remarks
OGM-342 Updating incorrect JavaDoc
OGM-426 Organizing tests in "core" module in two groups:

* Tests which only should be run once as part of the core module build ("test" package)
* Tests which should be executed for each datastore ("backendtck" package)
OGM-426 Running self-tests in utils only once
OGM-420 Making read preference configurable via a configuration property