Minify once, reduce build warnings (#692)

* Minify once, reduce build warnings

* Remove rollup-plugin-uglify

* address comment

rollup.config.js

@@ -1,58 +0,0 @@
-const commonjs = require('rollup-plugin-commonjs');
-const nodeResolve = require('rollup-plugin-node-resolve');
-const replace = require('rollup-plugin-replace');
-const babel = require('rollup-plugin-babel');
-const uglify = require('rollup-plugin-uglify');
-
-const DEV = !!JSON.parse(process.env.BUILD_DEV || 'true');
-const DEMO = !!JSON.parse(process.env.BUILD_DEMO || 'false');
-
-const plugins = [
-  babel({
-    babelrc: false,
-    presets: [
-      [
-        'es2015',
-        {
-          modules: false
-        }
-      ]
-    ],
-    plugins: [
-      'external-helpers',
-      'transform-object-rest-spread',
-      [
-        'transform-react-jsx',
-        {
-          pragma: 'h'
-        }
-      ],
-    ]
-  }),
-
-  nodeResolve({
-    jsnext: true,
-    main: true,
-  }),
-
-  commonjs(),
-
-  replace({
-    values: {
-      __DEV__: JSON.stringify(DEV),
-      __DEMO__: JSON.stringify(DEMO),
-      __BUILD__: JSON.stringify('es5'),
-    },
-  }),
-];
-
-if (!DEV) {
-  plugins.push(uglify());
-}
-
-module.exports = {
-  format: 'iife',
-  exports: 'none',
-  treeshake: true,
-  plugins,
-};