func (c *Conn) connect(display string) error {
	err := c.dial(display)
	if err != nil {
		return err
	}
	return c.postConnect()
}
connect connects to the X server given in the 'display' string,
and does all the necessary setup handshaking.
If 'display' is empty it will be taken from os.Getenv("DISPLAY").
Note that you should read and understand the "Connection Setup" of the
X Protocol Reference Manual before changing this function:
http://goo.gl/4zGQg
package xgb
import (
	"errors"
	"fmt"
	"io"
	"net"
	"os"
	"strconv"
	"strings"
)