Add logging facility in wire_log
Avoid busy loop in wire_log

When the logger is busy we can just sleep to avoid the busy loop.
Add readv/writev/preadv/pwritev to wire_io
Speed up wire_log stdout

Use writev to have a single round-trip to wire_io to write a single log
line instead of three writes.
Slightly larger test of stdout logger
Fix formatting of nsec part of time
Put log line data in a single struct
Add a semaphore to the locking methods
Support multiple log lines pending in the buffer

To reduce the chances of putting a wire to sleep have multiple log line
buffers to write into.
Provide a null logger to avoid crashes
Add method to resolve and connect to TCP service

This wraps the name resolving and TCP connection to simplify TCP
clients.