2014-02-10: fix links.

fix links.

diff --git a/README b/README
--- a/README
+++ b/README
@@ -23,8 +23,8 @@ Requirements
 * [Python 3.x][] for bootstrapping
 * [GNU Guile 2.x][] for running it
 
-[Python]: http://python.org "Python Programming Language"
-[GNU Guile]: http://gnu.org/s/guile "GNU Guile: The official extension language for the GNU operating system."
+[Python 3.x]: http://python.org "Python Programming Language"
+[GNU Guile 2.x]: http://gnu.org/s/guile "GNU Guile: The official extension language for the GNU operating system."
 
 Usage
 -----