Simplified EWSGI interfaces

Renamed WGI_RESPONSE_BUFFER as WGI_RESPONSE to avoid confusion
Removed EWF_HEADER and removed related caller from WGI implementation,
   now this is only part of WSF library
Added wgi_version, wgi_implementation and wgi_connector to the WGI_REQUEST interface
   to give more information to the user
Added back WGI_CONNECTOR to WGI specification, mainly because of `{WGI_REQUEST}.wgi_connector'
   simplified WGI_CONNECTOR to contain for now only `name' and `version'
   if the implementation of connector inherit from WGI_CONNECTOR (recommended)
   this might gives more access to the user using a reverse assignment for specific needs
   (but this usage is not recommended due to portability issue on other connector)
Removed useless connector.ecf since now EWF/WGI library provides the helper classes

library/server/ewsgi/specification/response/wgi_response.e

@@ -1,11 +1,10 @@
 note
-	description: "Summary description for {WGI_RESPONSE_BUFFER}."
-	author: ""
+	description: "Summary description for {WGI_RESPONSE}."
 	date: "$Date$"
 	revision: "$Revision$"
 
 deferred class
-	WGI_RESPONSE_BUFFER
+	WGI_RESPONSE
 
 feature {WGI_SERVICE} -- Commit
 
@@ -69,7 +68,7 @@ feature -- Status setting
 
 feature -- Header output operation
 
-	write_headers_string (a_headers: READABLE_STRING_8)
+	write_headers (a_headers: READABLE_STRING_8)
 		require
 			status_set: status_is_set
 			header_not_committed: not header_committed
@@ -80,18 +79,6 @@ feature -- Header output operation
 			message_writable: message_writable
 		end
 
-	write_header (a_status_code: INTEGER; a_headers: detachable ARRAY [TUPLE [key: READABLE_STRING_8; value: READABLE_STRING_8]])
-			-- Send headers with status `a_status', and headers from `a_headers'
-		require
-			status_not_set: not status_is_set
-			header_not_committed: not header_committed
-		deferred
-		ensure
-			header_committed: header_committed
-			status_set: status_is_set
-			message_writable: message_writable
-		end
-
 feature -- Output operation
 
 	write_string (s: READABLE_STRING_8)