changed token test output function to token member function

the Tester::printSmallToken() function that outputs to specified stream
was changed to Token::text() that returns a string, and updated called

this change is needed to put the translator output as a string into the
program view
created a very simple rpn list class

the new RpnList class inherits from Qlist<RpnItem *> and for now
contains empty constructor and destructor functions in new header file
implemented rpn list clear function

this function should be used to delete the RPN items in the list
instead of the user of the RPN list (translator upon error, or tester
after RPN list is output); there is now a source file for RpnList