added filters for releases and songs controllers
modified filters for admin artists controller
added some validations for admin banners, moved content of check_resources filter to actions in admin banners controller
modified filter for admin home, moved is_validate for update to actions of admin home controller
syntax tuned
added contents of filters for admin releases, admin live and admin songs controllers
moved is_validate filter for create and update of admin videos controller to create and update action
when visiting login page, redirect to admin home page if is_authenticated is true
added contents for actions in artists controller, open emtpy Artist model method
modified model method name
added content for actions of home controller
modified model method for temp use