trimmed newlines from post title and content description meta tags

In an article view, the meta tags containing content pulled from the markdown would contain a newline at their end, causing `">` to appear separately on the next line in the source. A harmless side-effect, but one that's easily fixed. These changes trim whitespace from the offending content when generating the tags.

The meta tags now also align at a nicer indent level.
The empty line added to `templates/simple/index.php` is intentional, to align the last meta item added by the simple theme.