Add sc3md instructions to README for Vagrant VM
Add norobots flag for hidden and draft layouts

It took a while to figure out how the layout front matter variable itself was working inside the different scopes/files, but this was much easier and cleaner than my original idea of listing the layouts inside of the head.html if statement.
Add Instagram iframe embeds, clean up whitespace
Add Instagram embeds to proposal post, tweak styles

Also, removed the exterior shot since it didn't add that much and didn't fit in the layout.