Fixed Ubuntu 12.10 bootstrapping of salt

Installs software-properties-common properly.
Moved warning to top of section.

Moved warning and added note that `sudo` is required.
Updated sample run line to have sudo.
Merge pull request #81 from jeffh/develop

Fixed the logic for installing `software-properties-common` on Ubuntu 12.10
Merge pull request #82 from rca/update_test_docs

Update test docs.

Bring more attention to the warning and mention the need to use `sudo`.
Merge branch 'develop' of github.com:saltstack/salt-bootstrap into develop
Add support for running a specific test case(by name).