BATCH-2007: Added a JobOperator implementation that complies with JSR-352.
* Added JsrJobOperator
* Added a ParametersConverter (and JSR-352 implementation) that converts parameters as specified by the JSR to JobParameters and back
* Added a method to the JobRepository to allow the direct creation of a JobInstance (since the JSR requires a new instance for each call to JobOperator#start
* Added a base context to be bootstrapped when the JobOperator is first referenced.  It provides things like a JobRepository, etc.
BATCH-2007: Refactored to use JobParametersConverter instead of new interface
Merge pull request #204 from mminella/BATCH-2007
BATCH-2008: Completed implementaiton of JSR-352 JobInstance, JobExecution and StepExecution
* Spring Batch's native JobInstance now implements the JSR's JobInstance interface.
* SB's JobExecution can be wrapped by a JSR's JobExecution.
* SB's StepExecution can be wrappedy by a JSR's StepExecution.
* A new JsrFlowJob and JsrFlowExecutor have been introduced to correctly handle the promotion of ExitStatuses during step execution.
* The JsrJobOperator has been fixed to correctly retrieve StepExecutions (previously was not returning fully hydrated verions).