improved the error handling.

now the serial communication class returns strings which are defined in the header file.
in addition to this there are now function which can check what kind of error returned
changed Signature of query TString to make it work from the command line.

the problem was that one cannot allocate an object in on binary (the dll) and delete it in another (CINT) , therefore it needs to be allocated in the interpreter beforehand
changed Signature of read TString to make it work from the command line.

the problem was that one cannot allocate an object in on binary (the dll) and delete it in another (CINT) , therefore it needs to be allocated in the interpreter beforehand