logbook: Use existing logger instead of `print`
selectiontool: Use existing logger instead of `print`

Also slightly reword message.
gui.util: Use logger instead of `print`
messagewidget: Use existing logger instead of `print`
Remove duplicated logging line, upgrade warning to error

We may or may not be performing as expected still, but the underlying
issue most probably is an actual bug and we should notify players.
`log.warn` => `log.warning`

Consistent with how logging is used everywhere else.
New logger gui.windows
New logger `changelistener`
singleplayermenu: Use logger instead of `print`
windowmanager: Use logger instead of `print`
changelistener: Use logger instead of `print`
Another `warn` to `warning` rename
Merge pull request #2183 from unknown-horizons/logging

Logging