Updated the PyPi classifiers
Use specified variant in debootstrap.
Put variant into setup in configuration file
Fix the HTTP proxy configuration for debootstrap
Added more information about variants

Also changed the layout around.
Handle variants for debootstrap and the configuration files

The variant can now be specified and alters the way that `debootstrap`
is run and the way that the `schroot` is entered.
Merge branch 'feature/variant' into develop
Bumped version number
Merge branch 'release/0.3' into develop