Connection class reorg in a testable state

[Warren Young]

Those interested in the recently proposed changes to Connection might 
want to check out what's in svn right now.  In particular, allow me to 
direct your attention to:

- Connection::Connection(db, server, user, password, port)
- Connection::connect(db, server, user, password, port)
- Connection::parse_ipc_method()
- TCPConnection (lib/tcp_connection.*)
- test/test_tcp.cpp

I'm done for the night, so I'll be creating the NamedPipesConnection and 
DomainSocketsConnection classes tomorrow at earliest.  There shouldn't 
be anything surprising in these; TCPConnection was by far the trickiest.