Update Python prerequisite in documentation

Author: Harmon758

doc/source/intro.rst

@@ -22,7 +22,7 @@ For performance critical 64 bit applications, a simplified version of memory map
 #############
 Prerequisites
 #############
-* Python 2.7 or 3.4+
+* Python 3.4+
 * OSX, Windows or Linux
 
 The package was tested on all of the previously mentioned configurations.