Letterman Gem & very basic CSS
Revert "Letterman Gem & very basic CSS"

This reverts commit 8ff023d260e525b20b619b7db1b638492c34e8a5.
Basic player mechanics added
Fix seeds to also confirm the user after creating it.
Show a (preliminary) 403 page, when a user is not authorized to perform some action.
Merge branch 'master' into user_interface