Code Cleanup

- Remove the code related to the format "day of year" (number of day starting
  from the January 1) as mktime does not allow to specify it with the field
  tm_yday.
- Cleaner check of the date (everything is done by Date::valid).
- Correct hour, minute and second is also checked.

src/Date.cpp

@@ -339,7 +339,7 @@ bool Date::valid (const int d, const int y)
   if (y < 0)
     return false;
 
-  if (d < 0 || d > 365)
+  if (d < 1 || d > Date::daysInYear (y))
     return false;
 
   return true;
@@ -371,6 +371,12 @@ int Date::daysInMonth (int month, int year)
   return days[Date::leapYear (year) ? 1 : 0][month - 1];
 }
 
+////////////////////////////////////////////////////////////////////////////////
+int Date::daysInYear (int year)
+{
+  return Date::leapYear (year) ? 366 : 365;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 std::string Date::monthName (int month)
 {