fixed issue with total interest still going up even if you're bi monthly (thanks for the catch, Jeremy)
fixed issue where it was inserting an extra comma if the value is negated (because it was counting - as a number since it was only set to skip the $)
made the title link either scroll to top of page on home or go back to index if on early payment page
insert ads every 25 rows in the payment table...man, I'm awful.  I might as well add microtransactions to this while I'm at it.