Lf2i

- Add ACORE and BFF test statistics
- Significantly improve computational speed via vectorizations and parallelizations
- Improve LF2I inference entry point and overall structure
- Accept pre-simulated datasets in LF2I.inference
- Add and improve plotting utilities for both parameter regions and coverage probability
- Refactor and fix bugs and inconsistencies
- Update tutorials and docs

First implementation of the framework, along with the Waldo test statistics and two complete tutorials.