First cut to truly async connect:

	- after connect(2), if async the connection is in "connecting" state
	- the first time a request is sent, "connecting" conns are polled
		- in case of success, the request is sent
		- in case still connecting, LDAP_X_CONNECTING is returned;
		  clients are expected to retry later
	- the "async" behavior must be explicitly enabled by setting
	  the LDAP_OPT_CONNECT_ASYNC option

"local" connections need work