Changed Space.collection() return type to Collection<IWorldTree>
Added get methods to PropertyDef.RandomSpec class
Moved earlyInit to WorldTreeFactory
Added get methods to AggExpr class
Removed ';' from Parser's skip list
All statements now expect ';' as terminating character
Added missing get method property() to IExpr
Added missing AGGREGATE keyword in PropertyDef.toString()
Manually set query field of PropertyDef upon RANDOM constructor
Working on materialization