Move everything into the new namespace starting with 'prosa' rather
than the bland 'rt'.

The main restructuring thrust is nearing completion, so let's get rid
of the `restructuring` namespace.

EDF is defined in terms of jobs, whether or not those jobs stem from
tasks. Make sure our definition is general enough to capture the
possibility of a set of jobs without associated tasks scheduled by
EDF.

This fixes all warnings about ambiguous module names and resolves #49.

It also highlights that we still need to cut down on superfluous
Require Import commands in recently ported files.