Display photo, video, and emojis in tweets; support of Twitter extended tweet format.

[jlj]

Hi Ryan,
This PR contains the fixes for a number of small problems I found when integrating MarkupTwitterFeed to my website.
Jean-Luc

• line 125: removed unnecessary require tmhOAuth/tmhUtilities.php;
• lines 165-175: if the communication with Twitter fails, fallback to the cache file, if it exists;
• line 197: fix an exception in method getIterator if getData returns false;
• line 250: make method renderItem public, so that it can be called from inside a foreach ($t as $tweetItem) loop.
  Example of use:

    $t = $modules->get('MarkupTwitterFeed'); 
    $renderOptions = array(
        'showDate' => 'before',
        'dateFormat' => __("M j, Y"), // Tweet block date format
    ); 

    foreach($t as $tweet) {
        if (strtotime($tweet['created_at']) >= $minTime) {
            $out .= $t->renderItem($tweet, $renderOptions);
        }
        else break; // tweet date before $minTime
    }

• lines 323, 327: replaced the incorrect configuration input field name cacheTime by cacheSeconds, so that the cache duration configuration is taken into account.