MODSERIAL with support for more devices

Dependents:   1D-Pong BMT-K9_encoder BMT-K9-Regelaar programma_filter ... more

Support for Nucleo F303K8

Add Nucleo F303K8 device support. Sadly uses TCIE (transmit complete) instead of TXEIE (transmit buffer empty), but this is what serial_api.c uses and the system doesn't work otherwise.

MODSERIAL with support for more devices Buffered, MODSERIAL, Serial