Update UserManager

- Not a model
- conpetual class
- singleton
Merge branch 'master' of github.com:jxWho/WishWall

Update UserManager
Merge branch 'JBLong'
Merge branch 'master' of https://github.com/jxWho/WishWall
Merge branch 'master' into JBLong

Conflicts:
	WishWall/application/classes/Wish.php
	WishWall/application/controllers/welcome.php
	WishWall/application/models/WishManager.php
为啥