Created separate method to deal with loading definitions
Removed creation of default properties file in constructor
Renamed default definitions file to world.definitions
Updated WorldTreeFactory storage types for properties and definitions
Renamed config to world.definitions
Updated constructor model for PropertyDef to be a lot cleaner
Renamed class TokenOperator to TokenCmpOp
Property class does not store value anymore
Added class TokenArithOp to parser package
Added Expr class and updated Parser
Most WorldTree related classes now implement Serializable
Added empty constructor to Space class to make it deserializable
Rewrote QueryTest class to be more flexible