an example

git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/branches/sshcommandendpoint-4698@36998 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb
finish explaining the example, perhaps

git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/branches/sshcommandendpoint-4698@36999 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb
just talk about auth instead of about private keys specifically

git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/branches/sshcommandendpoint-4698@37025 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb
Add a test for bad keys, fallback to password

git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/branches/sshcommandendpoint-4698@37335 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb
looks like this will not be needed, the ConchError that comes back is decently informational

git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/branches/sshcommandendpoint-4698@37336 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb
support key agents

git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/branches/sshcommandendpoint-4698@37337 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb