Add test for constraints

- Basic tests for difference in number of params, params at different
positions, etc.
Added verification for qid in constraints
Update arpeggio
Add validation of constraints in classifiers
Fix field iteration in OpParamAction
Add test for constraints on op/prop/param
Refactored commonly used parts into a function
Add test for duplicate parameters
Remove unnecessary parent model
Add reference check for operations
Fix error in param parsing
Remove mentor from list
Add rels