Implement an SSH module

A way to connect to remote machines and execute commands.
Supports proxying through a middle-machine to execute
commands on a target host.

To use:
    from satori import ssh
    client = ssh.connect("123.456.789.0")
    output = client.remote_execute('uname -v')
    # {'stdout': '#75-Ubuntu SMP Tue Jun 18 17:59:38 UTC 2013'}

To use with proxy:
    proxy = ssh.connect("10.11.12.99")
    client = ssh.connect("123.456.789.0", proxy=proxy)
    output = client.remote_execute('uname -v')
    # {'stdout': '#75-Ubuntu SMP Tue Jun 18 17:59:38 UTC 2013'}

Includes complete set of unit tests.
Decrements paramiko version to openstack standard.

Change-Id: I38abbc8910620f7055c790995ad5e1e5e8934337
Implements: blueprint ssh-module
Merge "Implement an SSH module"