Added webpack.ProvidePlugin for most used imports

Removed imports of React, connect, PropTypes throughout
Removed the "React" in React.Component/PureComponent

app/javascript/gabsocial/features/compose/components/search.js

@@ -1,5 +1,3 @@
-import React from 'react';
-import PropTypes from 'prop-types';
 import { defineMessages, injectIntl, FormattedMessage } from 'react-intl';
 import Overlay from 'react-overlays/lib/Overlay';
 import Motion from '../../ui/util/optional_motion';
@@ -11,7 +9,7 @@ const messages = defineMessages({
   placeholder: { id: 'search.placeholder', defaultMessage: 'Search' },
 });
 
-class SearchPopout extends React.PureComponent {
+class SearchPopout extends PureComponent {
 
   static propTypes = {
     style: PropTypes.object,
@@ -43,7 +41,7 @@ class SearchPopout extends React.PureComponent {
 }
 
 export default @injectIntl
-class Search extends React.PureComponent {
+class Search extends PureComponent {
 
   static contextTypes = {
     router: PropTypes.object.isRequired,