 Add internal selene visibility and missing dep to sketchrnn. (#1259)
 Add internal selene visibility and missing dep to sketchrnn. (#1259)

* Add internal derpdream visibility and missing dep to sketchrnn.

* update import name

* update import name

jesseengel/magenta,magenta/magenta,magenta/magenta,adarob/magenta,jesseengel/magenta,adarob/magenta