#27364: fix "incorrect" uses of escape character in the stdlib.

And most of the tools.

Patch by Emanual Barry, reviewed by me, Serhiy Storchaka, and
Martin Panter.
diff --git a/Tools/scripts/parseentities.py b/Tools/scripts/parseentities.py
index a042d1c..c686b02 100755
--- a/Tools/scripts/parseentities.py
+++ b/Tools/scripts/parseentities.py
@@ -14,7 +14,7 @@
 """
 import re,sys
 
-entityRE = re.compile('<!ENTITY +(\w+) +CDATA +"([^"]+)" +-- +((?:.|\n)+?) *-->')
+entityRE = re.compile(r'<!ENTITY +(\w+) +CDATA +"([^"]+)" +-- +((?:.|\n)+?) *-->')
 
 def parse(text,pos=0,endpos=None):
 
@@ -39,7 +39,7 @@
         if charcode[:2] == '&#':
             code = int(charcode[2:-1])
             if code < 256:
-                charcode = "'\%o'" % code
+                charcode = r"'\%o'" % code
             else:
                 charcode = repr(charcode)
         else: