add -h (previously add -host and -port)

Add the ability to specify the host and the port for the client/server, for exemple:

    #Change port:
    $>docker -d -h :5555&
    $>docker -h :5555 images

    #Change host to connect:
    $>docker -d #machine192.168.0.1
    $>docker -h 192.168.0.1 images #machine192.168.0.2

    #Change host and port
    $>docker -d -h 0.0.0.0:4444&
    $>docker -h :4444 images 

Fixes #573