Hierarchy of notes

[evanp]

We need to implement a hierarchy of notifications. I think the ol' syslog hierarchy is best:

• Error: error conditions
• Warning: warning conditions
• Notice: normal but significant condition
• Informational: informational messages

MUST requirements would be an error. SHOULD requirements would be a warning. Unusual style situations (like missing id or type) would be notice, and others would be info.

The validator should examine the parsed AS2 object, and determine notes about objects at each level. It should preserve the path to the level. Results might look something like:

• ERROR | top level | document was served as "application/json"; MUST be "application/activity+json"
• WARNING | top level | It's good to include a "@context" element in your top-level object.
• NOTICE | actor | No "id" defined for object.
• WARNING | object > attachment | No "name" property defined for object.
• INFO | target | Object is of type "foaf:Person"; an equivalent "Person" type exists in Activity Streams.