Added working version of Activity class, and improved activity unit tests
Person objects can can now hold and check activity object references
helper equals method
Stopped using arrays and started using hashes for activity person lookups
Added Activity Identifier method, and improved refs to modules
A room now holds references to the activity
..sent everytime set_room is called
No longer allowing modules to be changed after activity is constructed
Common code for all classes that hold refs to activities.
ATM these are Modules, Rooms and Persons
Added support for holding activity references
New unit tests, mainly to check activity references being handled properly