Backup / Restore

Hi Sam -

I added some backup/restore functionality.

I wanted to be able to save/load the blog data for two possible use cases:
1) If the mongo instance dies or fails, I want to have a copy elsewhere, but also that it is portable - that is, it can be reloaded on a new instance of the server. This lets me work on the blog locally, backup the blog data, scp it to my server, then 'restore' it there, and migrate / deploy blog updates a little more 'solidly'. I was afraid that editing the blog 'in place' with no ability to save it by itself would result in losing all the hard work.
2) Ability to do backups of just blog data.

Also added some usability:
- If you are editing a post, and you have not saved it, then show the save button.
- If you are editing a post, and you HAVE saved it, then show a "Return to List" button
- Added styling for links in the article - I found it impossible to see links in an article until you mouse over them.