split /admin/users into employees and guests list

add skeletton for /admin/users ; fix loading static files in /admin

add error handling and info messages handling for both front and admin

non-verified accounts must be notified with an error message.

add parseFacebookUserSession middleware; bugfix logged user middleware in requestPlugins.js ; some more bugfixes

add /api endpoint and make sure Guest accounts cannot access Admin

refactor router definition to controllers; mount sub app on /admin

implement iMeals default controller and admin controller ; 2 different themes used.