* Fix race condition on status in Relay.Publish method and failure to send
A race-condition exists between setting of the (unprotected) status and the callback which sets the status upon receiving an OK.
The message is sent which can receive an OK in separate goroutine (setting status) prior to the status being set to 'sent.'
The OK can be received prior to the status being set.
This fix also sets the status to PublishStatusFailed if the WriteJSON call fails.
* Add some NIP-11 extension structures to the RelayInformationDocument struct.
Added additional NIP-11 fields for relays that want to provide additional details based on NIP-11 extensions.
The retention structure has been left out as it doesn't have a clean schema for kinds (array of kinds, or pairs of kinds?)
Specified the fields w/ omitempty so marshaled will be same as original NIP-11 if nothing else is specified.
Nested structs defined as pointers so they are omitted if not specified.
* Fix TestPublishWriteFailed so that the socket is given a brief amount of time to close prior to publish being called.
The test relies on Publish always failing.
