Logging methods were renamed so they don't trigger go-vet warnings for
error() and Error() formatting.
Unit tests were updated to use new github.com/stretchr repo (was renamed
from stretchrcom)
Missing methods were added to Message mock object.
Most of the stuff in RFC1939 is implemented, and I was able to download
messages with Thunderbird. We do not yet purge deleted messages, and
probably need to implement some more auth modes.
