Update to elm 0.19 final

[rogeriochaves]

• [x] Remove custom binary from boilerplate
• [x] Update to final elm-webpack-loader (watch https://github.com/elm-community/elm-webpack-loader/pull/142) on boilerplate
• [x] Install Fresheyeball/elm-return instead of copied file (watch https://github.com/Fresheyeball/elm-return) on boilerplate
• [x] Update Spades itself from 0.18 to 0.19 (need to update stil4m/elm-syntax first)