Date: Collapsed 'sunday' and 'sun' into a closeEnough() call

- Removed the STRING_DATE_JANUARY_LONG and STRING_DATE_JANUARY_SHORT,
  replacing them with STRING_DATE_JANUARY and a call to closeEnough().
  This means you can enter 'jan', 'janu', 'janua', 'januar', 'january',
  instead of only 'jan' or 'january'.

src/Dates.cpp

@@ -136,6 +136,8 @@ bool namedDates (const std::string& name, Variant& value)
   int i;
 
   int minimum = CLI2::minimumMatchLength;
+  if (minimum == 0)
+    minimum = 3;
 
   // Dynamics.
   if (closeEnough ("now", name, minimum))