Changes to allow for SPI communication. MTS_SPI_Slave.cpp replaces MTSSerial.cpp. AT_SPI_Slave.ccp replaces ATSerial.cpp.

Dependencies:   MTS_SPI libmDot-dev-mbed5-deprecated

Fork of Dot-AT-Firmware by MultiTech

MTS-Serial.lib/shortlog@e2b8246361bc: not found in manifest