1. adding the runs (imsld instances) table
1.1. every property, role and instance is related with the run instead of the imsld_id
1.2. in the status table, the run_id is also stored
1.3. adding the UI to add and remove runs
1.4. passing as an argument the run_id in every function that has to do with the player
2. instantiating properties for new run
3. instantiating activity attributes and classes for each new run