Swift 3 support

Added swift 3 support.

Video to .gif

created method that converts video into images and then into a gif file
updated example project to show example of how create a gif from a image file
added video file in example project
updated podspec file

Background thread support

Added background thread feature to framework.
Updated example project

GIF file size

Fixed GIF file size log.

@Objc

Making class visible to ObjC projects

First release

Added pod FLAnimatedImage to show created gif on exemple view