Add Dialer type for creating client connections

[garyburd]

Add Dialer type for creating client connections:

type Dialer struct {
    // Dial specifies the dial function for creating TCP
    // connections. If Dial is nil, net.Dial is used.
    Dial func(network, addr string) (net.Conn, error)

    // TLSClientConfig specifies the TLS configuration to use with
    // tls.Client. If nil, the default configuration is used.
    TLSClientConfig *tls.Config

    // HandshakeTimeout specifies the duration for the handshake
    // to complete.
    HandshakeTimeout time.Duration

    // Input and output buffer sizes. If the buffer size is zero, then a default value
    // of 4096 is used.
    ReadBufferSize, WriteBufferSize int
]

func (d *Dialer) Dial(u *url.URL, requestHeader http.Header) (c *Conn, response *http.Response, err error)

[aglyzov]

Hey Gary,
I wonder what's wrong with Anoop's implementation of Dialer?
https://github.com/anoopk6/websocket

What issues does it have in your opinion? Maybe I could help resolving them?

[garyburd]

Fixed by 87accae