- changed name of './php/SessionSingleton.php' to './php/ASessionSingleton.php' to better reflect that it is an abstract class
- created './php/encountermanager/EncounterManager.php'
- './php/encountermanager/EncounterManager.php' now extends './php/ASessionSingleton.php'
- created class './php/actor/Actor.php'
- created class './php/dice/TwentySideDie.php'