[INFO] Enhancements to the CAN driver

[Giovanni]

Hi,

Some updates to this driver after a while...

1) Added I-class functions: canTryTransmitI(), canTryReceiveI().
2) TX event flags now report transmission errors in the upper 16 bits.
3) STM32 implementation received a configuration switch that silences excessive error reports. By default errors are only reported after the error rate goes past the warning and error thresholds.

I decided to not add callbacks, events are doing just fine. In OS-less mode (bare metal OSAL) events are implemented as callbacks so no loss.

Giovanni