docs: make gluon-batman-adv-15 the recommended batman-adv version

docs/releases/v2015.1.rst

@@ -55,6 +55,8 @@ Site changes
 
 * ``site.mk``
 
+  - ``gluon-mesh-batman-adv-15`` is now the recommended batman-adv version for new Gluon deployments.
+
   - The packages ``gluon-setup-mode`` and ``gluon-config-mode-core`` must now be
     added to ``GLUON_SITE_PACKAGES`` explicitly (to allow replacing them with
     community-specific implementations).

docs/site-example/site.mk

@@ -5,7 +5,7 @@
 #		The gluon-mesh-batman-adv-* package must come first because of the dependency resolution
 
 GLUON_SITE_PACKAGES := \
-	gluon-mesh-batman-adv-14 \
+	gluon-mesh-batman-adv-15 \
 	gluon-alfred \
 	gluon-announced \
 	gluon-autoupdater \