Improve Output

In every case where it is possible, we avoid `print` in favor of app-supplied methods.  This creates a much more maintainable and consistent way to get the right messages to the right places.

Highlights:

- Breaking change to move `--verbose` from a switch on the `server` command to a `duckpan`-wide switch
- Several complementary methods for outputting messages
- Drop word-based line-splitting on output
- Updates everywhere to replace `print`
- Convert old DOS line-endings to UNIX line-endings where appropriate

This should make it easier to produce reasonable output, even if you wanted a nice windowed application or something.

This builds on and includes the changes in #162.  It should not be merged if that PR is rejected for cause.
@killerfish Good spot.  There are a number of other completely undocumented options in there, but if I am going to document it I should aim for completeness!  Thanks.