use ISO8601 date + Volume for filename

This takes the partial date in the old filename and uses a full ISO8601 date for the new name, plus the Volume number from the Sierra Leone health site.

There are still problems with the data that need attention

1. The dates are all ahead by one day. 

The file "2014-08-13-v77.csv" contains CSV data that says 8/13/2014 from report 77.

The problem is the data *is* from report 77 but report 77 contains data from 2014-8-12 (it was reported on 2014-8-13).

2. the date field for Sep 25,26,27,30 use a 2 digit year, it should be 4.