Fix for #47

This code had been refactored but not tested with the no-armature workflow

io_scene_psk_psa/psk/builder.py

@@ -147,6 +147,8 @@ def build_psk(context, options: PskBuildOptions) -> Psk:
 
             # Temporarily force the armature into the rest position.
             # We will undo this later.
+            old_pose_position = None
+            if armature_object is not None:
                 old_pose_position = armature_object.data.pose_position
                 armature_object.data.pose_position = 'REST'
 
@@ -164,6 +166,7 @@ def build_psk(context, options: PskBuildOptions) -> Psk:
                 mesh_object.vertex_groups.new(name=vertex_group.name)
 
             # Restore the previous pose position on the armature.
+            if old_pose_position is not None:
                 armature_object.data.pose_position = old_pose_position
 
         vertex_offset = len(psk.points)