Whole bunch of um-pep8 style fixes.

plugins/3MFReader/ThreeMFReader.py

@@ -37,7 +37,7 @@ class ThreeMFReader(MeshReader):
         if extension.lower() == self._supported_extension:
             result = SceneNode()
             # The base object of 3mf is a zipped archive.
-            archive = zipfile.ZipFile(file_name, 'r')
+            archive = zipfile.ZipFile(file_name, "r")
             try:
                 root = ET.parse(archive.open("3D/3dmodel.model"))
 

plugins/3MFReader/__init__.py

@@ -2,10 +2,10 @@
 # Cura is released under the terms of the AGPLv3 or higher.
 
 from UM.i18n import i18nCatalog
-catalog = i18nCatalog("cura")
-
 from . import ThreeMFReader
 
+catalog = i18nCatalog("cura")
+
 def getMetaData():
     return {
         "plugin": {