- Moved the CONTENT_RANGE constant in to the Responses class because it is a response header name.
 - Made it possible to access the Ranges from within a RangesFile so that they can be checked for validity. They should neve be valid in the current implementation, but this cannot be assumed for all implementations in the future.
 - Refactored the File tests.
Centralised the FileHttpMessageConverter test code.
Added JavaDocs for the Range.toString() method.
Implemented a new RangesFileHttpMessageConverter that produces multipart responses for RangesFiles.
Finished off the support for multiple range queries.
Added the MimeType to the File interface.