Add Changelog entries for 0.5.5 and bump version to 0.5.5.

ChangeLog

@@ -1,3 +1,7 @@
+2015-12-07 Version 0.5.5
+    - Fix and test case for case insensitive subdomain matching.
+    - Python3 compatibility fixes and test cases thanks to Diane Trout
+
 2013-06-10 Version 0.5.4
     - Fixed error in FWS regular expression that cause some valid signatures
       to fail verification (Thanks to Peter Palfrader (weasel) for the patch)

README

@@ -1,7 +1,7 @@
 dkimpy - DKIM (DomainKeys Identified Mail)
 https://launchpad.net/dkimpy/
 
-Fork of:
+Friendly fork of:
 http://hewgill.com/pydkim/
 
 INTRODUCTION
@@ -11,7 +11,7 @@ signing and verification.
 
 VERSION
 
-This is dkimpy 0.5.4.
+This is dkimpy 0.5.5.
 
 REQUIREMENTS
 

setup.py

@@ -24,7 +24,7 @@
 from distutils.core import setup
 import os
 
-version = "0.5.4"
+version = "0.5.5"
 
 setup(
     name = "dkimpy",