Re-add autogenerated files

Signed-off-by: John Else <john.else@citrix.com>
Add installation instructions

Signed-off-by: John Else <john.else@citrix.com>
Use spotify-web-api

spotify-web is deprecated

Signed-off-by: John Else <john.else@citrix.com>
travis: Update OCaml and OPAM versions

Signed-off-by: John Else <john.else@citrix.com>