Update README.md

Author: dmalan

README.md

@@ -2,8 +2,6 @@
 
 [![Build Status](https://travis-ci.org/cs50/python-cs50.svg?branch=master)](https://travis-ci.org/cs50/python-cs50)
 
-Supports Python 2 and Python 3.
-
 ## Installation
 
 ```
@@ -19,13 +17,4 @@ pip install cs50
     c = cs50.get_char();
     f = cs50.get_float();
     i = cs50.get_int();
-    l = cs50.get_long(); # Python 2 only
     s = cs50.get_string();
-
-# References
-
-- https://github.com/ronsavage/SQL/blob/master/sql-92.bnf#L19-L72
-
-## TODO
-* Add targets for `pacman`, `rpm`.
-* Add tests.