Tried to reduce gap between both EWSGI proposals

Re-adapt the Spec-compliant solution (instead of Lib-compliant solution).
  Thus no more 100% deferred interface.
Rename EWSGI_RESPONSE into EWSGI_RESPONSE_BUFFER
Added in extra/response-as-result/  an copy/paste from the implementation of Paul's proposal (not up to date with Paul's spec). But this is mainly for information and tests.
Removed part of the ewsgi/specification interfaces ... to be able to test EWSGI compliant library against the pure specification (experimental).
Renamed most of the GW_... into EWSGI_...

library/server/ewsgi/src/extra/in_memory/gw_in_memory_response.e

@@ -0,0 +1,109 @@
+note
+	description: "Summary description for {GW_IN_MEMORY_RESPONSE}."
+	date: "$Date$"
+	revision: "$Revision$"
+
+class
+	GW_IN_MEMORY_RESPONSE
+
+inherit
+	EWSGI_RESPONSE_BUFFER
+		redefine
+			make,
+			commit,
+			write,
+			set_status_code,
+			write_header,
+			flush
+		end
+
+create {EWSGI_APPLICATION}
+	make
+
+feature {NONE} -- Initialization
+
+	make (a_output: EWSGI_OUTPUT_STREAM)
+		do
+			Precursor (a_output)
+			create header.make
+			create body.make (100)
+		end
+
+	header: GW_HEADER
+
+	body: STRING_8
+
+feature {NONE} -- Status output
+
+	write (s: STRING)
+			-- Send the content of `s'
+		do
+			body.append (s)
+		end
+
+feature -- Status setting
+
+	set_status_code (a_code: INTEGER)
+			-- Set response status code
+			-- Should be done before sending any data back to the client
+		do
+			status_code := a_code
+		end
+
+feature -- Output operation
+
+	flush
+		do
+			--| Do nothing ... this is in_memory response
+		end
+
+feature -- Header output operation		
+
+	write_header (a_status_code: INTEGER; a_headers: detachable ARRAY [TUPLE [key: STRING; value: STRING]])
+			-- Send headers with status `a_status', and headers from `a_headers'
+		local
+			h: GW_HEADER
+			i,n: INTEGER
+		do
+			set_status_code (a_status_code)
+			create h.make
+			if a_headers /= Void then
+				from
+					i := a_headers.lower
+					n := a_headers.upper
+				until
+					i > n
+				loop
+					h.put_header_key_value (a_headers[i].key, a_headers[i].value)
+					i := i + 1
+				end
+			end
+			header := h
+		end
+
+feature {EWSGI_APPLICATION} -- Commit
+
+	commit
+		local
+			o: like output
+		do
+			o := output
+			o.put_status_line (status_code)
+			o.put_string (header.string)
+			header_committed := True
+			o.put_string (body)
+			o.flush
+			Precursor
+		end
+
+;note
+	copyright: "2011-2011, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+	source: "[
+			Eiffel Software
+			5949 Hollister Ave., Goleta, CA 93117 USA
+			Telephone 805-685-1006, Fax 805-685-6869
+			Website http://www.eiffel.com
+			Customer support http://support.eiffel.com
+		]"
+end

library/server/ewsgi/src/extra/in_memory/gw_in_memory_response_application.e

@@ -0,0 +1,33 @@
+note
+	description: "Summary description for {GW_IN_MEMORY_RESPONSE_APPLICATION}."
+	author: ""
+	date: "$Date$"
+	revision: "$Revision$"
+
+deferred class
+	GW_IN_MEMORY_RESPONSE_APPLICATION
+
+inherit
+	EWSGI_APPLICATION
+		redefine
+			new_response
+		end
+
+feature -- Factory
+
+	new_response (req: EWSGI_REQUEST; a_output: EWSGI_OUTPUT_STREAM): GW_IN_MEMORY_RESPONSE
+		do
+			create {GW_IN_MEMORY_RESPONSE} Result.make (a_output)
+		end
+
+note
+	copyright: "2011-2011, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+	source: "[
+			Eiffel Software
+			5949 Hollister Ave., Goleta, CA 93117 USA
+			Telephone 805-685-1006, Fax 805-685-6869
+			Website http://www.eiffel.com
+			Customer support http://support.eiffel.com
+		]"
+end