Set size of each slab page via pillar (#19)

* make slab size changeable via pillar

* make slab size changeable via pillar for RedHat, too
diff --git a/README.rst b/README.rst
index 39808c3..9cdac65 100644
--- a/README.rst
+++ b/README.rst
@@ -17,6 +17,7 @@
       server:
         enabled: true
         cache_size: 64
+        slabsize: 1m
         bind:
           address: 0.0.0.0
           port: 11211