* v1.0.4

	add dispatch_once to `+ (void)load`

* v1.0.3

  fix the bug of crushing when device orientation changed

* v1.0.2
  
  fix the bug of cursh when using UIAlertView

* v1.0.1
  
  fix the bug crushing when more than one sections

* v1.0

   add cache for cell size height, improve efficiency（automatic invalidate）

* v0.7 

    add Support for StoryBoard prototype cell

* v0.6 

   fixed Height caculated bug and support Dynamic size cell

* v0.5 

    support to caculate size for UICollectionView Cell