[indian] Adding missing sample

Fix #47 (closed). The sample 'DatasetA/Training/nx23.jpg' was added to the 'default' protocol and to each of the 10 folds of the 'indian' dataset. This is the only missing sample and consequently the only addition to the protocols.

src/mednet/config/data/indian/default.json

 {
   "train": [
+    ["DatasetA/Training/nx23.jpg", 0],
     ["DatasetA/Training/nx52.jpg", 0],
     ["DatasetA/Training/nx19.jpg", 0],
     ["DatasetA/Training/nx38.jpg", 0],
@@ -85,7 +86,6 @@
     ["DatasetA/Training/px12.jpg", 1]
   ],
   "validation": [
-    ["DatasetA/Training/nx23.jpg", 0],
     ["DatasetA/Training/nx43.jpg", 0],
     ["DatasetA/Training/nx50.jpg", 0],
     ["DatasetA/Training/nx4.jpg", 0],