access the session-cookie easily in templates

Until now, you had to pass e.g. the username manually in every controller-method to render it in a template. Now, the values of the session-cookie will be added to every template and can be accessed by calling the key as variable in the template (this can be useful for an individualized header for logged-in users).

I don't know if this is a good solution. Maybe its better to add a variable to the application.conf and check whether this set to true? Another possibility may be to prefix all keys (like shown here: http://www.java2s.com/Tutorial/Java/0140__Collections/Clonesamapandprefixesthekeysintheclone.htm ). But this could lower the performance...