Fixes #272 by refactoring global log to conventional global... (#358)

* Fixes #272 by refactoring global log to conventional global as used by logzero

* Remove unnecessary logger from download_single, which was a test case

* Remove unnecessary logger from main(), which was a test case

spotdl/internals.py

@@ -1,9 +1,9 @@
 import os
 import sys
+from logzero import logger as log
 
 from spotdl import const
 
-log = const.log
 
 try:
     from slugify import SLUG_OK, slugify