General constructor for Black.Response.Instance.  (Close #11)
Switching the function Response.OK from returning a class-wide object to returning Response.Instance.  (Experimental.)
Making the response constructors primitive operations of Response.Instance.
Handling of content in requests.  Full implementation of output and partial implementation of input/parsing.  (See #13.  Close #14)
Making the reporting of un-implemented content parsing effective.
Improved error reporting.
Testing parsing of HTTP POST requests.
Merge https://github.com/AdaHeads/Black