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/components/icon_button.js

@@ -0,0 +1,96 @@
+import React from 'react';
+import { Motion, spring } from 'react-motion';
+import PropTypes from 'prop-types';
+
+class IconButton extends React.PureComponent {
+
+  constructor (props, context) {
+    super(props, context);
+    this.handleClick = this.handleClick.bind(this);
+  }
+
+  handleClick (e) {
+    e.preventDefault();
+
+    if (!this.props.disabled) {
+      this.props.onClick(e);
+    }
+  }
+
+  render () {
+    let style = {
+      fontSize: `${this.props.size}px`,
+      width: `${this.props.size * 1.28571429}px`,
+      height: `${this.props.size * 1.28571429}px`,
+      lineHeight: `${this.props.size}px`,
+      ...this.props.style
+    };
+
+    if (this.props.active) {
+      style = { ...style, ...this.props.activeStyle };
+    }
+
+    const classes = ['icon-button'];
+
+    if (this.props.active) {
+      classes.push('active');
+    }
+
+    if (this.props.disabled) {
+      classes.push('disabled');
+    }
+
+    if (this.props.inverted) {
+      classes.push('inverted');
+    }
+
+    if (this.props.overlay) {
+      classes.push('overlayed');
+    }
+
+    if (this.props.className) {
+      classes.push(this.props.className)
+    }
+
+    return (
+      <Motion defaultStyle={{ rotate: this.props.active ? -360 : 0 }} style={{ rotate: this.props.animate ? spring(this.props.active ? -360 : 0, { stiffness: 120, damping: 7 }) : 0 }}>
+        {({ rotate }) =>
+          <button
+            aria-label={this.props.title}
+            title={this.props.title}
+            className={classes.join(' ')}
+            onClick={this.handleClick}
+            style={style}>
+            <i style={{ transform: `rotate(${rotate}deg)` }} className={`fa fa-fw fa-${this.props.icon}`} aria-hidden='true' />
+          </button>
+        }
+      </Motion>
+    );
+  }
+
+}
+
+IconButton.propTypes = {
+  className: PropTypes.string,
+  title: PropTypes.string.isRequired,
+  icon: PropTypes.string.isRequired,
+  onClick: PropTypes.func,
+  size: PropTypes.number,
+  active: PropTypes.bool,
+  style: PropTypes.object,
+  activeStyle: PropTypes.object,
+  disabled: PropTypes.bool,
+  inverted: PropTypes.bool,
+  animate: PropTypes.bool,
+  overlay: PropTypes.bool
+};
+
+IconButton.defaultProps = {
+  size: 18,
+  active: false,
+  disabled: false,
+  animate: false,
+  overlay: false
+};
+
+export default IconButton;