SCPI interface to SX1272 and SX1276

Dependencies:   SX127x lib_gps lib_mma8451q lib_mpl3115a2 lib_sx9500 libscpi mbed

Issue: Request for a complete RXD/TXD demo

More complete demo for TXD/RXD is highly appriecated. It seems that my host script should poll the register to check if there is any packet arrival event, isn't it?