$base_url cleanup

Note that I haven't yet run the module, but have been looking at the code.

In meme.tpl.php there's an unused declaration of global $base_url

In memebrowser.tpl.php, it might be a little better to use l() instead of building up the ron-cron link with $base_url.

Also in memebrowser.tpl.php, the first print statement says "there's no memes" instead of "there are no memes".