Write a method that evaluates the "front-back" symmetry of a string up to matchLen letters from the front and back of the string. Return 'true' if the string is symmetric up to matchLen letters. Return false if matchLen is greater than half the string length, or if the letters don't match. For example, the string "racecar" will return true with a matchLen of 0, 1, 2, or 3, but not higher because a higher matchLen would be more than half the length of the string.