ptshih/PSCollectionView — pull request #26 by muer2000 (2013-06-05 05:56:40+00:00)
Title: Update PSCollectionView.m

1.Add vertical margin and horizontal margin.
增加纵向和横向间距属性。
2.Remove all rows that are not inside the visible rect and redundant.
修改移除可见视图的代码，用于解决reloadData全部刷新的问题