add -host and -port

Add the ability to specify the host and the port for the client/server, for exemple:

    #Change port:
    $>docker -d -port 5555&
    $>docker -port 5555 images

    #Change host to connect:
    $>docker -d #machine192.168.0.1
    $>docker -host 192.168.0.1 images #machine192.168.0.2

    #Accept only localhost connections
    $>docker -d -host 127.0.0.1&
    $>docker images #same machine

Fixes #573