Make dev-server use stderr

build/dev-server.js

@@ -8,3 +8,4 @@ const webpack = spawn('webpack', ['--config', 'build/webpack.dev.conf.js'], {
 
 const nodemon = spawn('nodemon', ['../dist/server', '--watch', 'server.js']);
 nodemon.stdout.pipe(process.stdout);
+nodemon.stderr.pipe(process.stderr);