creating AsyncSerialPort3 class and its testing tool. Finishing the renaming of the AsyncSerialPort1 testing tool.
implementig test for STRING_READ_WRITE test phase.
removing AsyncSerialPort3TestTask. For the creation of the AsyncSerialPortTestTask
creation of a unique testing task of the asynchronous ports (part 1).
creation of a unique testing task of the asynchronous ports (part 2).
implementing an overload test phase.