misc(README): update the README
refactor(directives): move some directives in a sub-directory
refactor(notifications): add a panel at the top of page
fix(notifications): correct notification useage
refactor(assign): change the behavior to assign instead of delegate
refactor(layout): work on layout and styles

and add some translations
refactor(tasks list): simplify and improve the listing of tasks
refactor(task): integrate the form of a task