Holidays and dates

- improved dateformat handling now defaulting to YMD set via
  dateformat.holiday variable
- fixed missing sorting in holiday table output when running
  calendar.holidays=full
- renamed reportdateformat to dateformat.report
- added config file checking for calendar.holidays and calendar.details
- added 2 holiday files for SE and US (watertown, MA)

src/tests/cal.t

@@ -138,6 +138,8 @@ if (open my $fh, '>', 'details.rc')
 {
   print $fh "data.location=.\n",
             "dateformat=YMD\n",
+            "dateformat.holiday=YMD\n",
+            "dateformat.report=YMD\n",
             "calendar.details=full\n",
             "calendar.details.report=list\n",
             "calendar.holidays=full\n",