Add link to reports from the main page
Fix issue of reports not showing zero days

On days where we have no clicks/impressions, the mapreduce job doesn't
create a zero row for that statistic. So when we show the data, it's as
if zeros don't exist. Hopefully, in the real world, this shouldn't
happen (i.e. zero impression days would be catastrophic for us). But
it's important to put this in so that we don't miss issues if we do
indeed have zero days.

Also fixed a minor refactoring issue around passing in the lastXdays
variable.
Bump