Call a response callback with an error if sending a message to the child failed.
LibcoapController.startDisconnectTimer should be @protected not @private.
Added the missing words to the disconnectTimeout comment.
`Zone.makeCancellable()` should be @public and not @private.
Wrapped `zone.setRemoteState()` response callbacks with `zone.makeCancellable()` and added descriptions to errors.
Updated californium-proxy to v0.1.1.
Added info about `config/cf-proxy.js` to README.md.