Code Kata - Roman Numerals

Introduction

Roman numerals, the numeric system used in ancient Rome, employs combinations of letters from the Latin alphabet to signify values.

http://en.wikipedia.org/wiki/Roman_numerals

1	5	10	50	100	500	1000
I	V	X	L	C	D	M

Challange

Convert Roman Numerals to Numbers

Instructions

Update the file roman_numerals.php so that you accept a Roman Numeral and return the equivalent Number.

To test your answer, run the index.php file with PHP.

Notes

Roman Numerals may be either uppercase or lowercase.