Good postings in here, go go friend zone denier team!
As was said earlier there is no friend zone. Always remember that. What you should be doing is making a move on her... What you're experiencing is similar to what I've seen in the past and this is what I mean:
1) What she says to other people about you is irrelevant... "oh he's just a friend!", "oh I wouldn't go out with him!"... Sometimes she might.actually be repulsed by you, but just trust.me when.I.say the things a girl tells her friends/other people about her feelings for you is often either meaningless or untrue. She can find you attractive and still tell her friends she thinks you're ugly.
2) What you experienced with her little kiss and flirting is something that holds true for practically all women. That is, in the heat of the moment a girl will be willing to go MUCH further with you than perhaps she has said.
What you should do:
Take her clubbing again, get her drunk, but this time you need to take things to the next level... Oh she kissed you on the cheek% Why didn't YOU take things further. I don't care that it was only a peck if she's okay to kiss you and is being flirty I am certain if you had started escalating she would've let you take it further. As has been suggested make out with her in the club. What she said to your friend about you two being "just friends", it means absolutely nothing, believe me.
You got this one in the bag trust me. The ONLY girls you have ZERO chance with are the ones who aren't comfortable with your touch in any way at all. If they aren't even okay with giving you a hug then there's something seriously wrong and she finds you repulsive, so you'd need to do a lot of work in that case, but with the majority of girls you can **** them by just escalating.
Sorry for ****ed up spelling and grammar I'm on a smartphone and typing out essays is a real b1tch.