Remove GitHub dependencies

[RubenVerborgh]

nodeSolidServer/node-solid-server#796 (comment)

[RubenVerborgh]

Working on this with:

• the publication on npm of http://npmjs.com/@solid/better-simple-slideshow
• the creation of https://github.com/solid/solid-panes/tree/v1.1.17
• publication of npm of the new solid-panes (pending permission)
• publication of new mashlib