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.

Add a [job_ready] parameter to the job model, akin to [pending], that
defines whether a job can be scheduled at a given time in a given schedule.

Then use this new general notion of readiness to define [backlogged].

A pending job may not be ready, whereas (under any reasonable
definition) a ready job ought to be pending, so this definition is
more precise and captures effects such as jitter and self-suspensions.

Maxime Lesourd authored 5 years ago and Björn Brandenburg committed 5 years ago

Add model definitions for work-conserving and priority-based preemptive schedules.

simplify structure of behavior, move arrival_sequence and schedule to toplevel, move task and sequential to model