Refactor tests for processing and adapt it to new library structure, plus fix...

Refactor tests for processing and adapt it to new library structure, plus fix unit tests for processing

qim3d/processing/_local_thickness.py

@@ -2,7 +2,7 @@
 
 import numpy as np
 from typing import Optional
-from qim3d.utils._logger import log
+from qim3d.utils import log
 import qim3d
 
 

qim3d/processing/_structure_tensor.py

@@ -3,7 +3,7 @@
 from typing import Tuple
 import logging
 import numpy as np
-from qim3d.utils._logger import log
+from qim3d.utils import log
 
 
 def structure_tensor(
@@ -108,7 +108,7 @@ def structure_tensor(
     val, vec = st.eig_special_3d(s_vol, full=full)
 
     if visualize:
-        from qim3d.viz._structure_tensor import vectors
+        from qim3d.viz import vectors
 
         display(vectors(vol, vec, **viz_kwargs))