Give output files sortable date & time format

Eg: “foo-report_2014-10-02_09-12-24-EDT.csv”.
Files named like this can be sorted by name and
will end up in chronological order. Year-month-day
is also a more international date format.
Merge pull request #43 from nathanl/sortable_timestamps

Give output files sortable date & time format
Add CSS classes to report to make styling easier