esockd_connection_sup should be redesinged

[Feng Lee]

esockd_connectoin_sup should not use supervisor with 'simple_one_for_one' mode..

esockd_connection_sup should be responsible for:

1. link or monitor all children
2. max connections controll
3. deny/allow access control

the most important issue is how to store pids of children?

dict? set? map? proccess dictionary?

[Feng Lee]

fixed in 2.2.x. use process_dictionary to store children pids