adding new status for the run: waiting (the users have't been assigned to the roles) removing useless code adding displayable_p field to the files table (display only one file for the resources) internationalizating
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