Apply diff2.txt from SF patch http://www.python.org/sf/572113

(with one small bugfix in bgen/bgen/scantools.py)

This replaces string module functions with string methods
for the stuff in the Tools directory. Several uses of
string.letters etc. are still remaining.

Tools/scripts/checkappend.py

@@ -35,14 +35,13 @@ __version__ = 1, 0, 0
 
 import os
 import sys
-import string
 import getopt
 import tokenize
 
 verbose = 0
 
 def errprint(*args):
-    msg = string.join(args)
+    msg = ' '.join(args)
     sys.stderr.write(msg)
     sys.stderr.write("\n")