[issue-276] Convert Datajs codes from V3 to V4. The major works should be: 1. Remove all the Json verbose logic, make the DataJS accepted and returned javascript object be in Json light format. (Since Json verbose has been completely removed on V4, making the javascript object returned by DataJS in json verbose format does not make sense any more. ) 2. Add the supports for parsing and setting the changed and new added headers in the request,response. 3. Parse OData V4 Metadata payload. 4. Make the DataJS cache and storage components work. 5. Batch payload parser and serializer. (Note: Serializer means serializing javascript object to the string payload which could be posted to OData service side, while Parser means converting the odata payload string to javascript object.)  6. Use javascript build-in functions to do Json light Payload parser and serializer. 7. Upgrade the test cases.
Merge branch 'OLINGO-276'