Doco

 1. improve coverage of Alien::Base
 2. more detailed synopsis
 3. description for Alien::Base::ModuleBuild
 4. mailing list meta

Please give me your feedback, I think the fuller synopsis and documentation of `Alien::Base` methods help a lot.  Right now you sort of have to go find an existing working example.
`instal_type` typo for `install_type`?