Resolve Issue #40: Python 2 print statements changed to use Python 3 print function (#50)

* Update 01_selection_sort.py

Updated last print statement for Python 3 print function.

* Update 01_countdown.py

Updated print statement to print function for Python 3.

* Update 05_quicksort.py

Updated print statement to print function for Python 3.

* Update 01_price_of_groceries.py

Condensed dictionary creation into one line, edited print statement to a print function for Python 3.

* Update 01_set_covering.py

Changed print statement to print function for Python 3.

* Update 01_binary_search.py

Changed print statements to print function for Python 3.

03_recursion/python/01_countdown.py

@@ -1,5 +1,5 @@
 def countdown(i):
-  print i
+  print(i)
   # base case
   if i <= 0:
     return