增加个方法以支持自定义$crypto_type呗

目前$type 是写死的，给个方法支持自定义呗。
```php
public function doSslHandshake($socket){
if (\feof($socket)) {
$this->destroy();
return false;
}
$async = $this instanceof AsyncTcpConnection;

/**
* We disabled ssl3 because https://blog.qualys.com/ssllabs/2014/10/15/ssl-3-is-dead-killed-by-the-poodle-attack.
* You can enable ssl3 by the codes below.
*/
/*if($async){
$type = STREAM_CRYPTO_METHOD_SSLv2_CLIENT | STREAM_CRYPTO_METHOD_SSLv23_CLIENT | STREAM_CRYPTO_METHOD_SSLv3_CLIENT;
}else{
$type = STREAM_CRYPTO_METHOD_SSLv2_SERVER | STREAM_CRYPTO_METHOD_SSLv23_SERVER | STREAM_CRYPTO_METHOD_SSLv3_SERVER;
}*/

if($async){
$type = \STREAM_CRYPTO_METHOD_SSLv2_CLIENT | \STREAM_CRYPTO_METHOD_SSLv23_CLIENT;
}else{
$type = \STREAM_CRYPTO_METHOD_SSLv2_SERVER | \STREAM_CRYPTO_METHOD_SSLv23_SERVER;
}
....
}
```

Start by locating the doSslHandshake($socket) method shown in the issue and read how the current $type is selected for asynchronous and non-asynchronous connections. Trace how SSL settings are configured, then make the crypto method selectable and verify that both connection paths use the configured value.

Written by the indexing model from the issue text.