Merge branch '2.3' into 2.5

* 2.3:
  [WIP] Adding a quick note explaining paramters.yml.dist a little
  Add a HiDPI favicon.

Author: fabpot

app/config/parameters.yml.dist

@@ -1,3 +1,4 @@
+# This file is a "template" of what your parameters.yml file should look like
 parameters:
     database_driver:   pdo_mysql
     database_host:     127.0.0.1
@@ -14,6 +15,8 @@ parameters:
     mailer_password:   ~
 
     locale:            en
+
+    # A secret key that's used to generate certain security-related tokens
     secret:            ThisTokenIsNotSoSecretChangeIt
 
     debug_toolbar:          true