Make indexPathsForVisibleItems return just the visible cells
Fix update for an insert to do a correct visibility check
Merge pull request #206 from educreations/develop

Make indexPathsForVisibleItems return just the visible cells
Add filter for cell layoutAttributes

In -[prepareForCollectionViewUpdates: prepareForCollectionViewUpdates:] the layoutAttributes for the footer accessory view were collected into _finalAnimationLayoutAttributesDict. This results in an -[NSArray addObject: nil] in -[PSTCollectionView indexPathsForVisibleItems] for a cell with no layoutAttributes.

By filtering the layoutAttributes in -[PSTCollectionViewData validateLayoutInRect:] to just the cell attributes we get the expected behavior.
Merge pull request #207 from educreations/master

Add filter for cell layoutAttributes
Fixes various typos in comments and headers
Called [super viewDidLoad] so that the view controller appears.
Added calls to [super viewDidLoad] so that the view controllers finish loading their views.
Added NSIndexPath+PSTCollectionViewAdditions.h/m to the projects so that calls to [NSIndexPath indexPathForItem:inSection:] work on pre-iOS 6.
Merge pull request #209 from guykogus/master

NSIndexPath error on iOS 5.x in demo projects
Always apply layout attributes. Fixes #203.
fix setCollectionViewLayout method's slowly & contentOffset setting
Merge pull request #210 from emeitch/fix_set_layout_offset

fix setCollectionViewLayout method's slowly & contentOffset setting
fix aborting at empty visibleItems
fix wrong predicates
Merge pull request #211 from emeitch/fix_set_collection_view_layout_bugs

Fix set collection view layout bugs
support iOS4.3
fix the issue that Supplementary datasource not called.
refactor, use property instead of raw ivar.
Merge pull request #213 from scutdavy/master

fix #212 Supplementary view invisible in ios 4.3
fix condition for layout invalidation