func EditScriptForMatrix(matrix [][]int, op Options) EditScript {
	return backtrace(len(matrix)-1, len(matrix[0])-1, matrix, op)
}
func EditScriptForMatrix(matrix [][]int, op Options) EditScript {
	return backtrace(len(matrix)-1, len(matrix[0])-1, matrix, op)
}
// EditScriptForMatrix returns an optimal edit script based on the given
// Levenshtein matrix.