add remote refs via validate.prefetch([], callback)
- add XHR + JSON.parse as default agent
- add async-each dependency

add back in ref, refRemote, definitions suite tests
- prefetch needed schemas for these tests
- add hack for getting around GitHub lack of CORS
- add test/server.js using Node/connect
- add package.json (for installing deps for test/server)

reimpl context.scope()
- add reference to parent, walk up tree
- context.graftContext() sets parent to target top-level
  schema; not this is not correct in some edge cases.

cache.add makes a shallow copy of the schema, adding in
the canonical id

add test/remotes to Makefile
cleanup

change cache.add to force canonical id (url) in copy
of schema
version bump (v0.1.1)