Dropzone is abandoned, update to new fork

[gumbarros]

beesofts this project has been abandoned by its author. I'm maintaining a fork over here: https://github.com/NicolasCARPi/dropzone but didn't look at hosting the doc yet.

Originally posted by @NicolasCARPi in dropzone/dropzone#2262 (comment)

[NicolasCARPi]

Good decision ;)