JSON LIBRARY UPDATES

+List of changes:

	1) test/in/person.jsch: Minor updates to make it a better example

	2) jsongen.erl:

		+Fixed object generator implementation: Optional properties are randomly generated (Either all optional properties can be generated in the json instance,
		or just a few of them (or none)).

		+Improved object generator implementation: 'required' keyword can be used in the json schema now. It is a list of properties which will be generated
		in all json instances (mandatory).