add proxy for rest partner connection with centralized exception handling
* Centralized place to work with the exceptions and see if a SalesforceSessionExpiredException should be thrown (for both Rest or Soap context). See SalesforceExceptionHandlerAdapter
* BaseSalesforceConnector#createBatchForQuery(...): removed code that will never be executed by using the adapter
* BaseSalesforceConnector#createBatchAndCompleteRequest(...):
(1) try{} scope was changed to just validate the BatchRequest#completeRequest(), as the previous line "getSalesforceRestAdapter().createBatch()" already has a proper exception handler in the adapter class SalesforceRestAdapter;
(2) replicated the exception handler to reconnect if necessary when parsing the request (TBD, this might be eliminated)
* SalesforceExceptionHandlerAdapter#analyzeSoapException: extracted same handler management here (TBD, check if the exception to be thrown in the else scenario shouldn't be the same exception, and not a wrapped one in a RuntimeException)
* Tests updated to make it work.
removing test
Merge pull request #71 from mulesoft/3.4.x-RestAdapter

3.4.x rest adapter