Initial commit
 - Added LXReorderableCollectionViewFlowLayout header and implementation.
 - Added an example that uses storyboard.
 - Setup README.md.
 - Uploads a screenshot.
 - Update README.md.
 - Implements missing behavior for auto scroll horizontally.
 - Provides a better fading between highlighted and normal item. (I hope)
 - Use delete/insert instead of move to prevent ghosting effect when dragging.
 - Don't invalidate the layout but instead performs batch update while panning. (Performance boost! :D)
 - Only apply layout attributes to cell. (Previously it applies to supplementary and decoration view too which is the wrong behavior)
This fix a bug when content size is less than collection view bounds, dragging the item to the bottom to activate auto scrolling cause the collection view to layout incorrectly.

Ideally I should have prevented the handleScroll from event activating but that will requires refactoring of that part of the code.
Fixed autoscrolling not working on when scroll direction set to horizontal. Embarrassing bug, stupid copying and pasting codes.
 - Improves the delegate methods naming convention.
When actual content size is smaller than the collection view bounds, provides an option (alwaysScroll) that still enable scrolling. This behavior is closer to the actual iBook so it is on by default.
 - Update README.md to reflect the latest change.
Provides additional but optional delegate callback for will/did begin reordering and will/did end reordering. There are runtime check for these optional delegate callback methods but from my opinion they are not in tight loop situation, so I find that there is nothing much to worry about.
 - Add codes that prevent clashing of events between default and custom long press gesture recognizer for collection view.
Ignore .DS_Store
Fix crash when displaying empty collection

- This flow layout will left align rather than force justify the collection.
Add delegate method to let it validate a reorder before it happens
Added an additional "should start reorder" delegate call.