XD-7 - Tuple data structure
The initial commit was designed to be backwards compatible with Spring Batch's FieldSet class.  Some differences, it does allow for non-String values and conversions from Strings to rich types are done through Spring ConversionService.  There are several TODOs in the code that need to be revisted on a subsquent iteration.  Some open questions are handling of null and default values.  Test code from Spring Batch's was ported over to help ensure backwards compatibility.