-Library to add and subtract two roman numerals without converting to decimal. -UNIT TESTED with CHECK.

RULES OF ROMAN NUMERALS: • Roman numerals consist of the following letters: I, V, X, L, C, D, and M which mean one,

five, ten, fifty, hundred, five hundred and one thousand respectively.

• As we are in Rome there are no such things as decimals or integers, we need to do this

with the strings. An example would be "XIV" + "LX" = "LXXIV."

• Numerals can be concatenated to form a larger numeral ("XX" + "II" = "XXII").

• If a lesser numeral is put before a bigger it means subtraction of the lesser from the

bigger ("IV" means four, "CM" means ninehundred).

• If the numeral is I, X or C you can't have more than three ("II" + "II" = "IV" not “IIII”).

• If the numeral is V, L or D you can't have more than one ("D" + "D" = "M" not “DD”).