Add an  extra "quint64" field for ZPnetEngine on bool connectTo (const QHostAddress & address , quint16 nPort,bool bSSLConn, quint64 extraData);
When user call connectTo actively to a remote address, this extra data can be remembered by network engine.
Same extra data value will be taken along with socket handle when
on_connect, on_recieveded or on_sended, on_disconnect... is called.
This approach is well used in another project "dataProxy" in my git resp.

Sloved a socket-error problem , when socket error happened, some cleaning works should be done immediately

* database confirm method in different threads, maximum 5 seconds /each check
* close current db connection when error take place.

Sloved a serious problem in heavily client login-logoff. add a rubbish can, hold sockets to be deleted later

There is still a problem in heavily-test.

const QByteArray & type paras, will cause lift cycle problems. using Value-pass instead.
----
QString, QByteArray supports ref-count and auto-delete , also, these classes support
least-copying, deep-copy will only take place, when the data is about to be changed.
so, in singnals and slots, using QString, QByteArray instead of const QString & and const QByteArray & ,
will not cause performance problem.

It is very strange, that in GNU C++ in Ubuntu, inline-member funcs called by different thread will return zero values.

Change message structure, Add an kick client method for plain client who want to connect to SSL port, or bad client send bad messages

Add openssl cert build basic execuables in windows 7, for convient

do not use Upper case chars in include filenames, which will cause file not found in unix-lke systems

operations in task line. adding event-loop based task thread pool.

1.Add linear hash alg from C code- an dynamic hash method, can effectively hash clients socket and their messages
2.generate several namespaces, avoiding name-conflicts

Load these certs at connect time. this is not good.