Merge pull request JS-Challenges#6 from aezed/master

Modified recursion test to check for calls > 1 rather than exact call…

spec/part1.js

@@ -28,7 +28,7 @@
         var originalFactorial = factorial;
         factorial = sinon.spy(factorial);
         factorial(4);
-        expect(factorial.callCount).to.equal(5);
+        expect(factorial.callCount).to.be.above(1);
       });
 
     });