Work-list based and Reps tabular slicing for recursive programs.

- Worklist approach implemented through a Config flag in SummaryTable.
- Unconstrained and constrained variantes (TabularAlgorithm & ConstrainedTabularAlgorithm). The constrained version features a limit to the size of the stack.
- Constrained subsumed variant for efficiency (ConstrainedSubsumedTabularAlgorithm).
- Efficient EdgeList (linked-list) to store edges visited through a traversal.
- Bump language level to 16.
- eKnife cli: added switch to use tabular algorithms.
- Moved benchmarks out of eKnife and BencherTest.