wxGUI: overlay rasters by default (merge from devbr6, https://trac.osgeo.org/grass/changeset/32767)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@32768 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/gui_modules/preferences.py

@@ -144,7 +144,7 @@ class Settings:
                     },
                 # d.rast
                 'rasterOverlay' : {
-                    'enabled' : False
+                    'enabled' : True
                     },
                 # d.vect
                 'showType': {