Draft: Paella7

This is a work in progress to update to Paella Player 7:

• Demo: http://158.42.8.193/
• Core repository: https://github.com/polimediaupv/paella-core
• Plugins repository: https://github.com/polimediaupv/paella-basic-plugins
• Slide plugins: https://github.com/polimediaupv/paella-slide-plugins