Fix aptitude reference in readme

Change-Id: I0806d5ba33f0c56f3b8533441c03d60ce56ee391
Don't use insecure tmpnam

This currently breaks Windows compatibility as the temp path does not exist.

Change-Id: Ia9da94530ece6d61d906471501390d7f6925ba45
Clean up whitespace

Change-Id: I0ff302ac2788edda42bb3e24505fa5122fcd599c