Removed implicit conversion from HTTP_CONTENT_TYPE to STRING_8

because it could be a source of bug due to hidden conversion (and parameters)
Applied changes to autotest cases
Cosmetic

library/server/wsf/tests/echo/src/echo_server.e

@@ -19,6 +19,7 @@ feature {NONE} -- Initialization
 			-- Initialize `Current'.
 		do
 			set_service_option ("port", 9091)
+			set_service_option ("verbose", True)
 			make_and_launch
 		end