1. ENHANCED: Statements are now asserted as IRIs (used to be blank nodes). This allows them to be dereferenced in the future.
2. DEBUG: Added various debug tools to keep track of model building and simulation (still ealy stages).
3. ADDED: Model exported now takes options and option presets (currently: plain, default).
4. CLEANUP: Disabled the use of a dedicated QR model exporter; trying to replicate existing behavior by setting existing options of generic RDF exporter.
5. ADDED: Wrapper around summation relation reader that returns reified statements.
6. DOC: Improved type annotations for QSIM readers.
7. ENHANCED: Added QSIM classes for reified statements (now IRIs).