added a wrapper around the templating engine, to be able to have default values
for some template variables.
{{! template of a 'rich' tweet displayed by the tweetsWidget
It's used only when we have access to the twitter api data (normally stored into
dc:source.content)
}}
<div class='Ldt-tweet_tweetContents'>{{{ contents }}}</div>
<div class='Ldt-tweet_date'>{{ date }}</div>