Abstract
1. Fix a bug that RJRefreshScrollHeaderView's bottomDelta will change RJRefreshScrollFooterView's bottomDelta value when they are both added into the same UIScrollView.

Detail
1. RefreshScrollDemo
RJPullDownCollectionViewController
RJPullCollectionViewController
RJPullDownTableViewController
RJPullTableViewController
  Remove the assignment of the bottomDelta property in parameter for refreshHeaderView.

RJPullUpCollectionViewController
RJPullCollectionViewController
RJPullUpTableViewController
RJPullTableViewController
  Remove the assignment of the topDelta property in parameter for refreshFooterView.

2. RefreshScroll
RJRefreshScrollFooterView
RJRefreshScrollHeaderView
  Reimplement setScrollView:hideFooter: method

3. Git configuration
.gitignore
  Add *.build ignore