Merge pull request #3 from zjjott/master

fix GetAction BUG
fix serverthread
add pooled threads
return thread to pool after session close
add simclient
remove unused member
fix simcommands and null return
add  ping command
typo
fix NPEs
update as a alias of add
typo
fix bug for sorting order
fix delete and typo
save function almost ready
save ready
add save code
finish save and load function;
use redis command:"save all" to save all key;
redis will load .dmp file when Simbase init.