Update development requirements
Let py.test generate the coverage html report
Improve the clean target in Makefile
Add Flask to package requirements
Store the selected backend in Conf class
Refactor the base Request class and its subclasses

Rework impractical code fragments. There was too much code for
too less functionality.

Remove "request_dict" headers from some methods (saving the request
dictionary in the as request-attribute)

Get the client id via extra method.
Replace the low level SocketServer with Flask
Fix get_logging_filehandlers_streams_to_keep

Also close the file handle to /dev/stdout.
Apply changes to the tests
Merge pull request #17 from bhedrich/develop

Develop