Character checking: be more verbose if something fails

This way one can easily debug what file causes problems

util/check_characters.py

@@ -29,13 +29,17 @@ else:
 print("### Reading in the following transcript files: ###")
 print(inFiles)
 
-
 allText = set()
 for inFile in (inFiles):
     with open(inFile, 'r') as csvFile:
         reader = csv.reader(csvFile)
+        try:
             for row in reader:
                 allText |= set(str(row[2]))
+        except IndexError as ie:
+            print("Your input file",inFile,"is not formatted properly. Check if there are 3 columns with the 3rd containing the transcript")
+            sys.exit(-1)
+        finally:
             csvFile.close()
 
 print("### The following unique characters were found in your transcripts: ###")