Better arrayAnswers.remove test data

Ensure that method works correctly on an array with two of the same value in a row.

For example, this method will pass the test in its current form, but contains a
flaw that is revealed when the test data includes two identical values in a row:

for(var i = 0; i < arr.length; i++) {
    if(arr[i] === item) {
        arr.splice(i, 1);
    }
}
return arr;

By removing arr[i] AND incrementing the index, the loop effectively tests only
every other array item, and will not remove all instances of the tested value.

[close rmurphey#185]

tests/app/arrays.js

@@ -21,6 +21,7 @@ describe('arrays', function() {
 
   it('you should be able to remove all instances of a value from an array', function() {
     a.push(2); // Make sure the value appears more than one time
+    a.push(2); // Make sure the value appears more than one time in a row
     var result = arraysAnswers.remove(a, 2);
 
     expect(result).to.have.length(3);