remove 'in development' from 0.8.8

Conflicts:
	CHANGELOG.txt

CHANGELOG.txt

@@ -61,7 +61,7 @@ Changelog
  * Added new translations for Croatian and Finnish
 
 
-0.8.8 (xx.xx.2015)
+0.8.8 (18.06.2015)
 ~~~~~~~~~~~~~~~~~~
 * Fix: Formbuilder no longer raises TypeError when submitting unchecked boolean field (Arne Schauf)
 * Fix: Image upload form no longer breaks when using i10n thousand separators (@signalkraft)

docs/releases/0.8.8.rst

@@ -1,6 +1,6 @@
-============================================
-Wagtail 0.8.8 release notes - IN DEVELOPMENT
-============================================
+===========================
+Wagtail 0.8.8 release notes
+===========================
 
 .. contents::
     :local: