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- Add definitions related to APA scheduling
- Prove correctness of reduction-based RTA for APA scheduling (FP and EDF)
- Add implementation of a weak APA scheduler
- Update definition of taskset to assume uniqueness
- Modify names and comments to improve readability
- Remove strong assumptions about priority order in FP scheduling
- Add tests with FP RTA for every model
- Add tests for RTA with parallel jobs

We use simpler, more pessimistic interference bounds to
prove that Bertogna and Cirinei's RTA works for parallel jobs.

- Implemented concrete job and tasks.
- Added a periodic arrival sequence.
- Created examples of applying a schedulability
  test to small task sets and concluding that
  no task misses a deadline.

- Now we have two definitions of work conserving, a simple version
  and another one based on count, along with a proof of equivalence.

- Implemented a concrete scheduler (basic and jitter)

- Removed unnecessary assumption in RTA about task precedence/no intra-task parallelism.
- Scheduler models and analyses are organized in separate modules/folders.
- Added RTA for FP and EDF for schedulers with release jitter.
- The scheduling invariants were split into more fine-grained assumptions:
  (a) scheduler is work-conserving
  (b) scheduler enforces FP/JLDP priority X
- New helper lemmas about counting, and sorted/uniq lists
- Inclusion of tactics feed and feed_n (see documentation).
- Added a Makefile generator