Added mc ffs 12m before interview determination

Uses denominator files from year of interview and previous year to
determine mc ffs status for the 12 months prior to the interview
Modified esrd code to look at interview year, not wave year
Finished coding indicators for any variable indicating serious medical
illness across claims and hrs
Finished coding for output ods file to get counts for Amy, need to
review it with her though for the medical definitions of all these
conditions.