PLT-2672 Refactored posts view with caching (#3054)

* Refactored posts view to use view controller design

* Add post view caching

* Required updates after rebase

* Fixed bug where current channel not set yet was causing breakage

webapp/components/permalink_view.jsx

@@ -5,7 +5,7 @@ import $ from 'jquery';
 import React from 'react';
 
 import ChannelHeader from 'components/channel_header.jsx';
-import PostFocusView from 'components/post_focus_view.jsx';
+import PostFocusViewController from 'components/post_view/post_focus_view_controller.jsx';
 
 import ChannelStore from 'stores/channel_store.jsx';
 import TeamStore from 'stores/team_store.jsx';
@@ -70,7 +70,7 @@ export default class PermalinkView extends React.Component {
                 <ChannelHeader
                     channelId={this.state.channelId}
                 />
-                <PostFocusView/>
+                <PostFocusViewController/>
                 <div
                     id='archive-link-home'
                 >