Protected gives body; PUT accepts exisitng files

The Protected builder provides a basic body for unauthenticated
requests.

The Dispatcher only sends to the PUT builder if the method is PUT AND
the file exists.
Adds ultra-simple Logger

The Logger has a static log field, and can statically add strings to the
log field. Needed for Basic Auth cobspec test.
MissingResourceBuilder logs requests to global log
ProtectedResource returns Logger's log as body