Add LiipThemeBundle

Re-defined the config / user relation to be OneToOne bidirectionnal.
ConfigType is now a service so I can inject the list of available themes that are also used by LiipThemeBundle

Force sqlite for test
In case of people use a different driver in parameter.yml (yes I do :))

app/config/routing.yml

@@ -19,6 +19,6 @@ logout:
     path:   /logout
 
 rest :
-  type : rest
-  resource : "routing_rest.yml"
-  prefix : /api
+    type : rest
+    resource : "routing_rest.yml"
+    prefix : /api