Nyzo 626: relay virtual hosting

Nyzo version 626 (commit on GitHub) adds virtual hosting capability to the relay server.

This version affects the relay server.

In RelayController, the host parameter is now read from the relay endpoints file if provided. An endpoint with an empty host parameter serves as a fallback for all requests, while an endpoint with a specified host parameter takes precedence for the specified host only.

The host field was added to the Endpoint class.

In the Endpoint.getParentEndpoint() method, the host field is now passed to the constructor for the parent.

The new Endpoint.getEmptyHost() method produces a copy of an Endpoint with the host field erased to the empty string.

The host is now considered in Endpoint.hashCode() and Endpoint.equals().

In WebListener.readMessageAndRespond(), the headers from the web request are now read into a Map.

For POST requests, the content-length header is now read from the headers map.

The host header is now used in building the Endpoint for requests.

In the WebListener.getResponse() method, the host of the Endpoint is now considered. Matching is performed according to the following priority:

• matching path, matching host
• matching path, empty host
• matching parent path, matching host
• matching parent path, empty host