Camera tracking integration

===========================

Set background to camera axis only when setting it from operator
in clip editor.

release/scripts/startup/bl_operators/clip.py

@@ -194,6 +194,7 @@ class CLIP_OT_set_viewport_background(Operator):
         bgpic.clip_user.proxy_render_size = user.proxy_render_size
         bgpic.clip_user.use_render_undistorted = user.use_render_undistorted
         bgpic.use_camera_clip = False
+        bgpic.view_axis = 'CAMERA'
 
     def execute(self, context):
         sc = context.space_data