Hmm, she ignores the not-texting-back and not-being-spontaneous clues too huh? I'd definitely notice that, but I guess some people just barge on. Maybe you should just try to keep ignoring her and do it more and more noticeably. Eventually she will notice, and if that's not the case, you could still tell her to back off.
Really, I've been in love with a good friend before which didn't quite work. When I realized she didn't have the hots for me, I backed off quite a bit for a few months because I knew my feeling would betray me if I would still act like its nothing. I hate to disappoint you, but I am afraid you're going to have to really back off, also as a friend, to shake her off your back. Really, if she's a nice friend, she will understand and things will get better once she's over it. If not, she's not worth being your friend.