PHP functions related to birthday

Including:

1. Getting the Zodiac sign (星座) of a date
2. Getting the symbolic animal (生肖) of a date
3. Getting the Life Path Number (生命灵数) of a date
4. Calculating the age (年龄)
5. Calculating the years matching the symbolic animal within a range of years (or ages)
6. Calculating the year of birth from actual age, where age increment is on the birthday
7. Calculating no. of days since born
8. Calculating no. of days to the next birthday
9. Calculating no. of days from the last birthday
10. Check whether this year's birthday has already passed
11. Check whether a date has passed Chinese New Year of the year
12. Getting the Chinese New Year date of a year (range from 1876 to 2163)