Make file reader selection case insensitive by using ext.lower() and update...

Make file reader selection case insensitive by using ext.lower() and update config_text_reader.py to point to renamed dictionary.

instruments/dictionaries/ICAD.yaml

@@ -119,3 +119,20 @@ table_header:
     description: Sample source
     units: unspecified
     rename_as: sample_source
+    
+  # NO2 additional vocabulary terms
+
+  CHOCHO (ppb):
+    description: CHOCHO concentration
+    units: ppb
+    rename_as: chocho_concentration_ppb
+  CHOCHO Uncertainty (ppb):
+    description: Uncertainty in CHOCHO concentration
+    units: ppb
+    rename_as: chocho_uncertainty_ppb
+
+  10_#ICEDOAS iter.:
+    description: Number of ICEDOAS iterations
+    units: unspecified
+    rename_as: icedoas_iterations
+