Added buttons and menu items to dismiss individual notifications (#76)

* Added DELETE verb for notifications

* Added notification dismiss button to status dropdown

* Added reveal-on-hover notif dismiss button, added FollowNotification component

app/controllers/api/v1/notifications_controller.rb

@@ -24,6 +24,10 @@ class Api::V1::NotificationsController < Api::BaseController
     render_empty
   end
 
+  def destroy
+    dismiss
+  end
+
   def dismiss
     current_account.notifications.find_by!(id: params[:id]).destroy!
     render_empty