Renumber CS exercises after move

Author: mao-sz

…science/recursion/13_factorial/README.md …_science/recursion/1_factorial/README.mdcomputer_science/recursion/13_factorial/README.md renamed to computer_science/recursion/1_factorial/README.md computer_science/recursion/13_factorial/README.md renamed to computer_science/recursion/1_factorial/README.md

@@ -1,4 +1,4 @@
-# Exercise 13 - Factorial
+# Exercise 1 - Factorial
 
 Write a recursive [factorial](https://simple.wikipedia.org/wiki/Factorial) function that takes a non-negative integer, and returns the product of all positive integers less than or equal to the input integer. An input of `0` should return `1`. The function should only accept numbers, so `'4'` should not be accepted as it is a string. All invalid inputs should return `undefined`.
 

…ence/recursion/13_factorial/factorial.js …ience/recursion/1_factorial/factorial.jscomputer_science/recursion/13_factorial/factorial.js renamed to computer_science/recursion/1_factorial/factorial.js computer_science/recursion/13_factorial/factorial.js renamed to computer_science/recursion/1_factorial/factorial.js

@@ -1,4 +1,4 @@
-# Exercise 14 - contains
+# Exercise 2 - contains
 
 Write a function that searches for a value in a nested object. It returns true if the object contains that value.