Fix for issue 323. Decoration views do not display properly.
Removed reuseIdentifier which was no longer used along with two unused methods.
If the layout isn't prepared, then prepare it when it's about to be used
Fix associated object disappearing

The associated object gets cleared out in invalidate layout, so it
makes sense to add it in prepare layout. Otherwise, once the layout has
been invalidated once, the associated object is gone forever and won't
ever be created again.
Use modern syntax
Fixes issue with class generation
Fixed crash while moving items from a section different to 0, tested and working.
Merge pull request #338 from camitox/master

Crash while moving Cells - Tested on iOS 5.1
Use bounds instead of frame in the delegate method asking for invalidation.
Invalidate layout on bounds change.
Mark the collection view data as valid, also in case of the early bail-out.
updated podspec to 1.1.0 tag
Correctly decoding reuseIdentifier when loading from Nib
Merge pull request #346 from nxtbgthng/fix/reuseidentifier-from-nib

Correctly decoding reuseIdentifier when loading from Nib
Merge pull request #345 from Soph/master

Updated .podspec for 1.1.0 release
Merge pull request #343 from nxtbgthng/feature/fix-collection-data-updateItemCounts

Bug fix in  -[PSTCollectionViewData updateItemCounts]
Merge pull request #342 from nxtbgthng/feature/invalidate-on-bounds-change

Invalidate Layout on Bounds Change
Dequeue CollectionCell - apply the attribute (bounds) only once in method applyLayoutAttributes:
Fixes #340 (Calls viewDidLoad after lazy loading the collectionView.)
Merge pull request #326 from mattjgalloway/missing-assoc-object

Fix associated object disappearing