Provide interface to upload a Markdown post from file

[durden]

I really like writing editing my posts in vim (insert your favorite editor here). So, I'd like to be able to somehow write all of my posts in Markdown. I could just easily copy/paste my text file into the web UI. However, it'd be nice to not have to deal with this.

Another use case is that I don't have Internet access for a few days, but I wrote several posts. Now I would like to post them all, but don't want to do this copy/paste dance. It might be a nice feature to just have some way to upload some posts from a file, etc.