Added TAPE_THROW_EX and TAPE_THROW_CODE macros to automatically add file, line

and function strings to tape exceptions.  Example usage:

  TAPE_THROW_EX(castor::exception::Internal,
    ": Failed to down cast reply object to tapegateway::FileToRecall");

  TAPE_THROW_CODE(EBADMSG,
    ": Unknown reply type "
    ": Reply type = " << reply->type());

Fixed bug in RTCOPY protocol; we were sending one too many "end of file lists".

Fixed bug in message dispatch logic, there was a missing break in one of the
switch statements that was causing an IObject to get dynamic casted to two
different classes.