TOD mapping for hourly counts in validation script

[goreaditya]

It appears that the hour to tod mapping for value 20 is incorrect. Currently it is set to '18to20' but should be associated with '20to5' based on other values in the dictionary. https://github.com/psrc/soundcast/blob/35faa3ea606f22e30a40256ef585d555a2de45d2/scripts/summarize/standard/validation.py#L87

This can be fixed by replacing the line with the following: 20:'20to5',

Please add any notes here if my interpretation of tod_lookup is incorrect.