Migrate to Swift 4.2

Migrate Swift source to v4.2 and add settings for new iphone frames

bug fix

found a crash on removeAllItems method that would cause crash when items' size is 0

Add Setting for number of items per screen

Introduce new properties to allow set number of items per screen for multiple screen sizes instead of setting minimum margins, as well as new properties to center subviews when items are not wide enough to use whole screen width

Add custom width and support multi screen sizes

Add custom width when judging whether to scroll to next item; add
support to all Apple devices screen size, now you can specified
different mini margin, mini appear width and left margin for all sorts
of screen sizes.

Adapt Swift 3 with Xcode 8

Change to adapt Swift 3 with Xcode 8, add support to nib, just change
the class on nib file to ASHorizontalScrollView

Adapt Swift 3 and fix bug

change C style code to swift 3 format, fix removeItemAtIndex last index crash bug

Adapt iOS 9.0 & Swift 2.1

Objective-C: Add comments on functions, remove scale when calculating margin, it seems that the behaviour in iOS 9 change the way of align views

Swift: Change to adapt Swift 2.1, add comments on functions, remove scale when calculating margin, it seems that the behaviour in iOS 9 change the way of align views

First Version

Swift 1.2