如果client非正常退出，server端的client list不会将立即该client清除，当reload时，server端会foreach
client list，当调用该client时便会block
将client注册时，将proxy的timeout设置300，防止block发生
Merge pull request #1 from prstcsnpr/master

解决server端会block的bug
Merge https://github.com/sinofool/dbpool into bbc: direct use
client->ice_timeout(300) is ok

Conflicts:
	server/dbpool_server.cpp
add compare in set
1. add log to debug and error
2. when return data to remote client, return a copy
3. add compare for set