Replace sprockets/browserify with Webpack (#2617)

* Replace browserify with webpack

* Add react-intl-translations-manager

* Do not minify in development, add offline-plugin for ServiceWorker background cache updates

* Adjust tests and dependencies

* Fix production deployments

* Fix tests

* More optimizations

* Improve travis cache for npm stuff

* Re-run travis

* Add back support for custom.scss as before

* Remove offline-plugin and babili

* Fix issue with Immutable.List().unshift(...values) not working as expected

* Make travis load schema instead of running all migrations in sequence

* Fix missing React import in WarningContainer. Optimize rendering performance by using ImmutablePureComponent instead of
React.PureComponent. ImmutablePureComponent uses Immutable.is() to compare props. Replace dynamic callback bindings in
<UI />

* Add react definitions to places that use JSX

* Add Procfile.dev for running rails, webpack and streaming API at the same time

app/javascript/mastodon/features/home_timeline/components/setting_text.js

@@ -0,0 +1,38 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+
+class SettingText extends React.PureComponent {
+
+  constructor (props, context) {
+    super(props, context);
+    this.handleChange = this.handleChange.bind(this);
+  }
+
+  handleChange (e) {
+    this.props.onChange(this.props.settingKey, e.target.value)
+  }
+
+  render () {
+    const { settings, settingKey, label } = this.props;
+
+    return (
+      <input
+        className='setting-text'
+        value={settings.getIn(settingKey)}
+        onChange={this.handleChange}
+        placeholder={label}
+      />
+    );
+  }
+
+}
+
+SettingText.propTypes = {
+  settings: ImmutablePropTypes.map.isRequired,
+  settingKey: PropTypes.array.isRequired,
+  label: PropTypes.string.isRequired,
+  onChange: PropTypes.func.isRequired
+};
+
+export default SettingText;