serial_common.c/h. decouple runtime_config from serial ports. decouple
buzzer from serial ports. decouple opening of the main serial port from
the msp code. decouple serial rx providers from runtime_config. rename
core_t to serialPorts_t since it only contained serial ports. It's now
clear which files use serial ports based on the header files they
include.
Keil project not updated, I have no way to verify it.
Note, mw.c, drv_pwm.c and drv_system.c contain code for too many topics.
Later commits will relocate the code as appropriate.
Not even looked at utils yet. 'Utils' is a bad naming practice and is a
synonym for 'too lazy to find the right file/name'.
Update software serial to support RX, TX or RX&TX modes. Update serial
API to allow on-the-fly changing of serial port mode. Update HoTT to
change serial port mode when transmitting.
