Add podspec
Modify podspec.
Boost `layoutAttributesForElementsInRect` performance.
fixed rendering bugs with small number of cells
Merge pull request #19 from ddwang/master

fixed rendering bugs with small number of cells
Coding style adjustment.
More coding style adjustments.
Update podspec.
Add header support
Merge pull request #24 from neilkimmett/master

Add header support
Update podspec.
Add a 'respondsToSelector:' check for 'collectionView:heightForHeaderInLayout:'
Add footer support
Merge pull request #25 from olivercameron/delegate-header-selector-check

Add a 'respondsToSelector:' check for 'collectionView:heightForHeaderInLayout:'
Add footer support
Merge branch 'neilkimmett-master'
Coding style adjustments and some codes cleaning.
Update header and footer
Update some demo codes.
Update podspec