Pre-condition: actor must be able to touch the object. This doesn't require that the actor is actually holding the object, but the actor must be able to physically touch the object. This ensures that the actor and object are not, for example, separated by a transparent barrier.

If there is a transparent barrier, we will attempt to remove the barrier by calling the barrier object's tryImplicitRemoveObstructor method. Objects that can be opened in an obvious fashion will perform an implicit recursive "open" command, and other types of objects can provide customized behavior as appropriate.

touchObj :   TouchObjCondition