Added upgrade tree

You should talk with me on skype if you want to edit something...
Merge branch 'master' of https://www.github.com/mid-kid/CookieClickerTD
Merge branch 'master' of https://www.github.com/mid-kid/CookieClickerTD
Merge branch 'master' of https://www.github.com/mid-kid/CookieClickerTD