[zhuao]finish function of create group
Merge branch 'master' of https://github.com/wrasdf/iEat

* 'master' of https://github.com/wrasdf/iEat:
  iOS | Order link
  iOS | show staticstics of orders
  iOS | show dishes of group
  iOS | Extract group details to GroupTabBarController
  iOS | refactoring
  iOS | text for empty group list
  iOS | Show restaurant list via new api
  iOS | Show active group via new api
  iOS | 重构