* Updated the job-repository tag to allow for a serializer and deserializer to be injected
* Updated the XStreamExecutionContextStringSerializer to implement Serializer and Deserializer
* Replaced the ExecutionContextStringSerializer with the ExecutionContextSerializer interface
* Updated the XSD and parser to accept the injection of an implementation of the ExecutionContextSerializer from the job-repository tag
* Updated the JdbcExecutionContextDao to use injected ExecutionContextSerializer implementation
Reference: https://jira.springsource.org/browse/BATCH-1684