Get CouchDB data directory
Use 'knox' for S3. Load config from file.

 * Use 'knox' for its 'putFile' method, for easy
   streaming of files to S3. 
 * Load credentials from a standard AWS 
   credentials file.
 * Specify other settings in config.json
Config: Add defaults, dev config file
Ignore local .aws folder

AWS credentials might be stored in the .aws
folder, as that is the practice recommended by
Amazon.
Remove unused .gitignore lines

The GitHub defaults for .gitignore has things
we don't use, and now they're gone.