ordinalDayFromMarchFirst function

int ordinalDayFromMarchFirst (int month, int day)

Return the day of the year counting March 1st as 1, after which the number of days per month is constant, so it's easier to calculate. Formula from http://en.wikipedia.org/wiki/Ordinal_date

Implementation 

int ordinalDayFromMarchFirst(int month, int day) =>
    ((30.6 * month) - 91.4).floor() + day;