Gen Info Page - Zip Code - Mismatch causes error

[jkneifel]

If the user inputs a ZIP code not in our database, it will not run. We can resolve this by either:
(1) run a check that the zip code is valid and provide an error message
(2) complete a closest match to the database instead of an exact match
(3) Resolve #136

I prefer (3), but if we can determine whether an easier solution is best for now.