Make tasks and waitingTasksCount protected
Make tasks and waitingTasksCount protected

Making tasks array and waitingTasksCount protected would allow developers to extend the AssetsManager and add custom tasks, such as a FontFileAssetTask. This would be useful for situations like http://www.html5gamedevs.com/topic/23989-custom-fonts-in-canvas2d/ where a third party library is used to load font faces before Text2D renders. BabylonJS might not want to add a FontFileAssetTask due to the overhead, but it would be helpful for developers that want to maintain the AssetsManager pattern without duplicating the entire code.
RaananW/Babylon.js,abow/Babylon.js,Kesshi/Babylon.js,sebavan/Babylon.js,jbousquie/Babylon.js,abow/Babylon.js,NicolasBuecher/Babylon.js,Hersir88/Babylon.js,NicolasBuecher/Babylon.js,Temechon/Babylon.js,RaananW/Babylon.js,RaananW/Babylon.js,BabylonJS/Babylon.js,BabylonJS/Babylon.js,BabylonJS/Babylon.js,Hersir88/Babylon.js,NicolasBuecher/Babylon.js,jbousquie/Babylon.js,Kesshi/Babylon.js,abow/Babylon.js,Kesshi/Babylon.js,sebavan/Babylon.js,Temechon/Babylon.js,jbousquie/Babylon.js,Temechon/Babylon.js,sebavan/Babylon.js,Hersir88/Babylon.js