Attempt StringIO after failed BytesIO file read

This is a bandaid to allow the --input-url option to be used to read in single files. It adds zero functionality beyond what already existed when the --input-file option was used.

test/Controller_test.py

@@ -71,7 +71,7 @@ def test_controller_input_url():
         "--output-url",
         "file://" + tmp_dir + "/{obs}{date:%Y%m%d}_XYZF_{t}{i}.{i}",
     ]
-    
+
     # parse arguments and create initial args object
     args = parse_args(fake_argv)
 
@@ -103,7 +103,7 @@ def test_controller_input_url():
         "--output-url",
         "file://" + tmp_dir + "/bou20181024_XYZF_noURL_vmin.min",
     ]
-    
+
     # parse arguments and create initial args object
     args = parse_args(fake_argv)