Allow for greater theming flexibility

Here is a patch that adds greater flexibility for theming the quotes, particularly in the quotes block. Before, the quotes block would only show $node->body, which is the legacy (4.7.x) way of rendering things. This patch changes that so the block shows the results of drupal_render($node->content). In addition, I wanted to be able to only show a snippet of the quote in the block. So I took advantage of the teaser/body part of nodes. So now, when preparing the text for the quotes block, it calls quotes_view with the teaser flag set to true. This in turn calls theme('quotes_teaser', $node), which can be themed however the end user wants, but just defaults to printing out the teaser of the quote.