The package ignored errors from net.Conn Set*Deadline in a few places.
Update the package to return these errors to the caller.
Ignore all other errors reported by errcheck. These errors are safe to
ignore because
- The function is making a best effort to cleanup while handling another
error.
- The function call is guaranteed to succeed.
- The error is ignored in a test.
Fixes#441.
Issue #441 specified a message separator. This PR has a message terminator. A message terminator can be read immediately following a message. A message separator cannot be read until the start of the next message. The message terminator is more useful when the reader is scanning to the terminator before performing some action.