Fixed recursion error in binary_search_by_recursion

[antfitch]

In binary_search_by_recursion, if you search array for a value that does not exist, you will get this error:

RecursionError: maximum recursion depth exceeded in comparison

To fix this, first check to make sure that the value is between left and right points like this:

if (right < left):
    return None

A similar construct has already been applied to binary_search, but did not exist in the recursive alternative.