For this lab, we will practice using the map and filter functions.

Part 1)
Using the map function, implement a strings-to-nums function.
This function takes a list of string representations of numbers
and converts them to the numbers themselves.  Example:

   (strings-to-nums '("1" "2"))  ->  '(1 2)


Part 2)
Using map, write a function that takes a list of list of first names
and a list of last names and produces a list of full names.
You may assume that the lists are of equal length.

Part 3)
Using the filter function, write a function that takes a list of employees
and returns a list containing only managers.

The Codecheck url is http://codecheck.it/files/1806110801amh1vk2x1z0d4aubd5ardp7id.