Blacken all Python files

Using the black code reformatter, pass it over all our Python files.
This allows for a consistent style across the code base.

Exception: lumps/dmxgus/stats.py, for readability.

graphics/text/rotate

@@ -23,5 +23,5 @@ else:
     img2 = img2.crop()
 
 if os.path.exists(sys.argv[3]):  # delete any previous result file
-	os.remove(sys.argv[3])
+    os.remove(sys.argv[3])
 img2.save(sys.argv[3])