Move logic for file-system based resources to Resourceful project

[Marak]

Blacksmith currently has it's logic for reading and writing Article resources hard-coded into blacksmith itself.

This is wrong. We should have generic logic available for handling file-system based resources. This logic should be pulled out of blacksmith and added to the Resourceful project.

We also should re-think how the file-system resource logic currently works, it's not exactly ideal yet, particularly in regards to smart updates based on mtime and ctime.

See:

https://github.com/flatiron/blacksmith/blob/master/lib/fs2.js
https://github.com/flatiron/resourceful/