Inserting cells without initialLayoutAttrs bugfix

(now using regular layoutAttrs with fade-in using alpha)
Merge pull request #164 from gavrix/bugfix

Inserting cells without initialLayoutAttrs bugfix
Added the UIView designated initializer
Merge pull request #165 from smule/master

Override the UIView designated initializer in PSTCollectionView
Fix highlighting behavior and reorganize how selection and highlighting iteract
fix incompatible pointer type warning for Deployment Targets >= iOS 6.0
Merge pull request #169 from mikevoyt/fixwarnings

fix incompatible pointer type warning for Deployment Targets >= iOS 6.0
Merge pull request #166 from taiyangc/highlight

Fix highlighting behavior and reorganize how selection and highlighting ...
Update header
- fix targetContentOffsetForProposedContentOffset:withScrollingVelocity: not called
- relay UIScrollViewDelegate methods to _collectionViewDelegate
Added invalidateLayout implementation for PSTCollectionViewLayout.m
Merge pull request #176 from r618/master

Added invalidateLayout implementation for PSTCollectionViewLayout
Fix to effectively ignoring contentInset with a small contentSize.
Removed the minimum contentSize setter in -[PSTCollectionViewFlowLayout updateItemsLayout].
PSTCVFlowLayout -updateItemsLayout takes into accout PSTGridLayoutSection.sectionMargins to set contentSize.
Merge pull request #177 from loganmoseley/master

-[PSTCollectionViewFlowLayout updateItemsLayout] changes to correct contentSize.
Merge pull request #170 from lono175/master

Fix "targetContentOffsetForProposedContentOffset:withScrollingVelocity:" not called
Preserve ivar layout.