renamed AI_Model to AIModel for consistency, added it as a functioning drop-down select on settings page, added face_distance to db and code, put face_distance model_used into all classes ready for use

TODO

@@ -1,26 +1,37 @@
 ## GENERAL
 
-    * face locations:
-        START FORM SCRATCH so all images have face_locn data
-        right now GenThumb is in shared, and does width, height as well --> in person.py BUT need this for pa_job_manager
-        -- show face locns in viewer.html [DONE]
-            * how hard would bootstrap 5 be, and use form-switch instead of 'badge'
+    * Face matching:
+        - upgrade to face distance per face per file
+            - so we dont get 2 x same face in one file, and if it could match say Cam and Mich for 1 face, take the higher match, not the first one to be over the threshold
+        - allow for threshold/settings to be tweaked from the GUI?
+            ---> at least settings for default value (back to 0.6 / 0.5?)
+            ---> with override table to do per file / per face?
+        - face locations:
+            START FORM SCRATCH so all images have face_locn data
+        - algo:
+            for each face (even known) in image
+                foreach refimg
+                    get face_distance
+            sort by face_distance
+            for each face
+                connect lowest score with that face (for this file)
+                this means this face is no longer 'free' for a match
+                if (sorted) face distance > 0.55 stop as no further 'matches'
+        - use cnn model (check ftst.py) for ref images, and potentially as a setting to check images without a face?
+        - or always?
+            -- would CUDA be useful here? (which is faster say an old 730 or the AMD cpu?)
 
-    * allow for threshold/settings to be tweaked from the GUI
-        - it would be good to then say, just run the scanner against this image or maybe this DIR, to see how it IDs ppl
-        ---> settings for default value
-        ---> override table to do per file combos?
-
-    * refimg 
-        - remove AI menu from top-level -> make a sub-of Person, and just have Match or AI
+    
 
     * viewer:
         can we make it preload next/prev images, and only reload the image div when we jump?  to make arrow-based nav much faster
 
     * remove dirs after the duplicate cleanup removes all its content
-    * fix up logging in general
+
     * could look to remove the hand fixing of json.loads of array data --> seems you can make your own datatype in the ORM, and it can do the conversion every time you use it
         - https://stackoverflow.com/questions/28143557/sqlalchemy-convert-column-value-back-and-forth-between-internal-and-database-fo
+
+    * fix up logging in general
     * comment your code
     * more OO goodness :)