Facebook's annual F8 developer conference is a showcase for the new features and updates coming to the company's array of services. Messenger is already one of the top IM apps and the company is looking to rebuild the user experience from the ground up. The key themes for this year will be Messenger's push into privacy and its focus to bring a faster way of interacting with your close friends and family. The first major change with the new Messenger app will be its repackaged smaller footprint which Facebook calls "LightSpeed". The new app will reportedly come in at less than 30MB and...