Control activation behavior per machine.

This changes the default to enforce activation of the configuration,
unless you set "deployment.alwaysActivate" to false on a specific
machine.

Of course the --always-activate switch still has the same meaning as
before, so you can even enforce activation on machines that have
alwaysActivate set to false.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>