logging: set root logger level/handler

This keeps the root logger from swallowing logs, for example logs
emitted by plugins and dependencies (such as the MusicBrainz API
client).

Author: 9999years

beets/ui/__init__.py

@@ -1638,10 +1638,16 @@ def _configure(options):
     config.set_args(options)
 
     # Configure the logger.
+    root_logger = logging.getLogger()
+    if not root_logger.handlers:
+        root_logger.addHandler(logging.StreamHandler())
+
     if config["verbose"].get(int):
         log.set_global_level(logging.DEBUG)
+        root_logger.setLevel(logging.DEBUG)
     else:
         log.set_global_level(logging.INFO)
+        root_logger.setLevel(logging.INFO)
 
     if overlay_path:
         log.debug(