Archive template mutates the shared site.posts array

The Archive template is mutating the site.posts array directly using .reverse(). (https://github.com/davemo/blog.davemo.com/blob/f6e8b014003c126a985d1cd4ed45e81a097da72c/app/templates/archive.us#L9)

The archive is the last file generated prior to the RSS feed. However, grunt-markdown-blog has a bug with the RSS feed such that it is only grabbing the X *oldest* posts. (It's grabbing the first X posts in the ascending-sorted posts array). So, the bug with archive.us is actually masking the grunt-markdown-blog bug. :smile: 

grunt-markdown-blog v0.2.4 fixes this bug, so upgrading would expose the archive.us bug. (End result would be an rss feed only showing the very first 10 posts from 2008 or so.)