Review Actions interface

[flowersinthesand]

Actions is a powerful interface to define a specific event using Action and usually used internally by event firer. Typically, it backs up method like oneventname(Action<Event> action) internally and change in Actions doesn't affect event firer's API. Though, since it's very useful, it would be nice for user to use it for their own purpose. However, the following points should be considered to encourage doing that.

• Interface name
  Actions is vague name and is named from jQuery's Callbacks object that was inspiring to write Actions interface. ActionStack, ActionPipeline or EventDefiner, and so on look better.
• A way to configure option
  I'm not sure which way is better among setter, POJO option, option builder, and so on but clearly it's not needed to change such option in runtime as it defines a specific event.
• Flow control
  Considering various events, flow of executing action should be able to be controlled by event firer or listener. Sometimes actions should be executed in a row asynchronously or synchronously and also sometimes firing should be stopped by some condition. (For example, a process to find proper cettia transport in client may be one of usages using this.) Many ways are available: 1. A special class extending ThreadLocal to acquire flow controller 2. A special action to control flow 3. A special method on Actions to control flow. We need to find more flow control cases and determine how to achieve that. Substituting event object in firing event may be required as well.
• Benchmark Netty and Grizzly
  Both frameworks have similar component e.g. Pipeline and Filter. See what functionalities should be provided.