Also:
* add -verbose flag to cmd/tailscale netcheck
* remove some API from the interfaces package
* convert some of the interfaces package to netaddr.IP
* don't even send IPv4 probes on machines with no IPv4 (or only v4
loopback)
* and once three regions have replied, stop waiting for other probes
at 2x the slowest duration.
Updates #376
Under some conditions, code would try to look things up in the maps
before the first call to updateLatency. I don't see any reason to delay
initialization of the maps, so let's just init them right away when
creating the Report instance.
Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
