use PureComponent for performance

src/basic/Content.js

@@ -1,14 +1,14 @@
 import { connectStyle } from 'native-base-shoutem-theme';
 import PropTypes from 'prop-types';
-import React, { Component } from 'react';
+import React, { PureComponent } from 'react';
 import { SafeAreaView } from 'react-native';
 import { KeyboardAwareScrollView } from 'react-native-keyboard-aware-scroll-view';
 
 import variable from '../theme/variables/platform';
 import mapPropsToStyleNames from '../utils/mapPropsToStyleNames';
 import getStyle from '../utils/getStyle';
 
-class Content extends Component {
+class Content extends PureComponent {
   static contextTypes = {
     theme: PropTypes.object
   };