Povray: Fix bunch of issues after recent refactor.

Those were breaking automated tests, since (un)registering was not
working properly. Mainly:

* Use `hasattr` instead of try/except when batch-assigning to a variable
  that does not always exist.
* Fix some incorrect call to sub-`register()` from parent `unregister()`
  functions.
* Remove double definition (in two different files) of World's pov
  textures.

1 files changed, 1 insertions, 5 deletions

diff --git a/render_povray/texturing_gui.py b/render_povray/texturing_gui.py
index 6d12fb62..ad889f43 100755
--- a/render_povray/texturing_gui.py
+++ b/render_povray/texturing_gui.py
@@ -49,12 +49,8 @@ from bl_ui import properties_texture
 
 for member in dir(properties_texture):
     subclass = getattr(properties_texture, member)
-    try:
+    if hasattr(subclass, "COMPAT_ENGINES"):
         subclass.COMPAT_ENGINES.add('POVRAY_RENDER')
-    except BaseException as e:
-        print(e.__doc__)
-        print('An exception occurred: {}'.format(e))
-        pass
 del properties_texture