Add dev python dependencies (#367)
Add dev python dependencies (#367)

* Add dev python dependencies

Include instructions for installing scipy and matplotlib manually when developing on magenta.

* Fix typo

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