Reorganise constants, and add ISO language codes in order to drop dependency pycountry

tests/nwdummy.py

@@ -2,7 +2,7 @@
 """novelWriter Test Dummy GUI Classes
 """
 
-from nw.enum import nwAlert
+from nw.constants import nwAlert
 
 class DummyMain():
 

tests/test_gui.py

@@ -12,7 +12,7 @@ from nw.gui.dialogs.projecteditor import GuiProjectEditor
 from nw.gui.dialogs.timelineview  import GuiTimeLineView
 from nw.gui.dialogs.itemeditor    import GuiItemEditor
 
-from nw.enum import *
+from nw.constants import *
 
 keyDelay  = 10
 stepDelay = 50

tests/test_project.py

@@ -12,7 +12,7 @@ from nw.config          import Config
 from nw.project.project import NWProject
 from nw.project.item    import NWItem
 from nw.project.index   import NWIndex
-from nw.enum            import nwItemClass
+from nw.constants       import nwItemClass
 
 theConf = Config()
 theMain = DummyMain()