add changelog/release notes for page_published signal

CHANGELOG.txt

@@ -7,6 +7,7 @@ Changelog
  * Explorer nav now rendered separately and fetched with AJAX when needed
  * Added decorator syntax for hooks
  * Replaced lxml dependency with html5lib, to simplify installation
+ * Added page_unpublished signal
 
 0.4.1 (14.07.2014)
 ~~~~~~~~~~~~~~~~~~

docs/releases/0.5.rst

@@ -35,6 +35,7 @@ Core
         )
 
  * The lxml library (used for whitelisting and rewriting of rich text fields) has been replaced with the pure-python html5lib library, to simplify installation.
+ * A ``page_unpublished`` signal has been added.
 
 
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