Experimental port of animated-gif-lib-for-java to ScalaJS.

A Scala.js port of https://github.com/rtyley/animated-gif-lib-for-java, Roberto Tyley's repackaging of Kevn Weiner's animaged GIF processing classes: http://www.fmsware.com/stuff/gif.html.

Project goals: Demonstrate Read/Write capabilities for animated GIF files in Web Browser JavaScript execution contexts.