Add failing test for add nested in an open search

This is because Net::LDAP::Connection#add calls read without queueing,
meaning it can read the wrong message off the socket.
Use queued_read for Net::LDAP::Connection#add
Merge branch 'master' into queue-reads-everywhere

Conflicts:
	lib/net/ldap/connection.rb
Unit test queued_read and usage
Use queued_read in modify
Can't use keyword args in 1.9
Use queued_read for rename operation
Use queued_read for delete operation
Use queued_read for start_tls
Use queued_read for bind_simple
Use queued_read for bind_sasl
Merge pull request #144 from ruby-ldap/queue-reads-everywhere

Queue reads everywhere