Add message type

Add message type, re-organize some files to have a more consistent layout.
Add to tab completion, etc.
be sensitive to piping: do not require input name

Detect when stdin is being piped and automatically use it without
requiring '-' as the input name.  Default action is still to print
help with no args.
hyperlink everything through, enable local hyerlink lookups

Apparently enabling one changes the lookup for all over them.
Now that they are all on the web, I'm more comfortable doing this.
Merge pull request #7 from tidepool-org/bewest/adding-messages

Thanks to @jebeck for extra testing!