Swift 4

• Migrate to Swift 4
• Support a placeholder for input tagging slot
• Add a delegate method to determine if an inputed text should be accepted or not
• Fix minor bugs

1.2.2

• Expose some UI controls to customize more easier
• Fix reference cycle with delegate (thanks. @MainasuK )

Conforming with Swift 3

Add escaping directive to a closure parameter.

Converting to Swift 2

1.1.4