constants file so as to not repeat constants between CLI and lib.

adds an option to ask for and store the ssh password from the cli

Don't use a shell and thus avoid a whole class of problems

Use a mktemp'd path for uploading modules

Fall back to standalone simplejson module

CentOS5 has python 2.4 which doesn't have a built-in json
module

TODO: add a command to auto-add a host, list hosts, etc