重构pigeon客户端逻辑，修改为filter chain实现
添加服务端处理Process Filter类实现
将InvocationFilter分拆为InvokeFilter和ProcessFilter
将InvocationFilter分拆为InvokeFilter和ProcessFilter
重构request的context设置方式
Merge pull request #6 from liuliliujian/master

暂时没大的问题，由于是重构先合并进来，最后在统一确保代码没问题；
调整请求响应回来后从repository中移除该请求的逻辑到finally块中
add DpsfThreadPoolExecutor
remove bin
Merge pull request #19 from firefox007/master

扩展JDK ThreadPool
change context value from string to serializable
Merge branch 'master' of https://github.com/dianping/pigeon
add fail-over cluster implementation
add proxybeanfactory's cluster and customizedfilter config
mockFilter