Implemented WSF_RESPONSE.put_error (...) and related

Added WSF_RESPONSE.put_character
Renamed  WGI_OUTPUT_STREAM.put_character_8 as put_character  to follow style of put_string  (and not put_string_8)
Refactored the WSF_DEFAULT_SERVICE_LAUNCHER
Added WSF_DEFAULT_SERVICE to be more user friendly
Splitted the wsf/default/ libraries to have wsf/connector/... and being able to handle more than one connector in the same application

library/server/libfcgi/implementation/fake/fcgi_imp.e

@@ -55,6 +55,14 @@ feature -- FCGI output
 			io.put_string (a_str)
 		end
 
+feature -- Error
+
+	put_error (a_str: READABLE_STRING_8)
+			-- Put `a_str' on the FastCGI stdout.
+		do
+			io.error.put_string (a_str)
+		end
+
 feature -- FCGI Input
 
 	read_from_stdin (n: INTEGER)