Jordan Mansfield/Getty Images Ross Barkley has had an up and down time at Chelsea since signing a year ago, and he clearly feels there’s more “up” to come. Speaking on the Chelsea official website, he revealed that he still feels he has a long way to go in his development: “I feel like in a short space of time I’ve developed really well. I feel as though I can still improve a lot. We’re still getting used to our style…