every and each unmounting...

从 Observable 的 AutoUnmount 行为以及 issue 中提到的 Browser::Interval 和 Browser::Delay 类开始。检查 every、each、every! 和 each! 当前如何处理卸载，然后确定应实现所提议的哪些语义以及哪种 override 行为。选定的计时器生命周期行为保持一致，并由项目的相关测试覆盖，即视为完成。

every makes sense, as the timer will keep running for ever. But should any each timer that is still running when things unmount also be unmounted? Note that Observable includes AutoUnmount, so any store will get this behavior as well!

Then, on the other hand, there is an each! and every! method (they don't auto start, so you have to say each!(x).start. Neither of these timers IS auto-unmounted.

Couple of options:

1. just take after out of unmount, and forgettabout it.
2. 1 + provide a remove_after_timers method callable in Observable
3. leave it, and if you want a timer that isn't unmounted use the bang variation.
4. provide auto_unmount(x) attached to the timers so you say: after(12).auto_unmount(true) or every(12).auto_unmount(false) to override the defaults.

Currently I think its best to make both every and every! behave the same, and make each and each! not autounmount, and then add the auto_unmount method to the Browser::Interval and Browser::Delay classes.

  attr_accessor :mount_point

  def auto_unmount(yes)
     # warning message  and return if mount_point is nil
     if yes 
      AutoUnmount.objects_to_unmount[mount_point] << self 
     else
      AutoUnmount.objects_to_unmount[mount_point].delete(self)
    end
  end

  alias unmount abort

now all the automounter does is set mount_point

     def every!(*args, &block)
        super.tap do |id| 
           next id if unmounted?
           id.mount_point = self
           id.auto_unmount(true)
         end
      end
      def after!(*args, &block)
        super.tap { |id| id.mount_point = self unless unmounted? }
      end