Added a partial content test for the RangeFile.
Cleaned up a string.
Updated the RangeFile class so that it only accepts valid ranges. Also updated the FileController to support this new behaviour.
Refactored the response specific utility methods into the Responses class.
Removed the range validity check in the RangeFileHttpMessageConverter and added an early failure instead, because invalid ranges shouldn't be making it to this class.
Added a JsonIgnore annotation to the RangeFiles inputStream so that it is not serialised. Also updated the FileSteps so that no other File implementations leave this out.
Updated the range vararg Ranges constructor so that it now makes sure all the Ranges have the correct fileSize.
Created a new RangesFile class that will be used to build multipart range responses.