Document required STK500v2 driver for flashing C5 from Windows.
Merge remote-tracking branch 'origin/next' into next
Log general information about CAN traffic every 5s.
Log bus stats across all buses every 5s.
Log the message drop rate from CAN.
Bump up CAN message queue to avoid some message drops.
Bump to v4.1 for release.
Merge remote-tracking branch 'origin/master' into next
Use -y flag in CI setup to avoid timing out.
Force float conversion when calculating bus statis per second.

This fixes a divide by zero error on the PIC32.
Fix floating point conversion in log output.
Log output interface statistics.
Log data transfer rate for all output interfaces.
Increase CAN message rx queue to avoid drops.
Clean up language with bus stats logging.
Calculate proper maximum frequency for outgoing signals.

This is a breaking change as it alters the functionality of the
sendFrequency attribute on a CanSignal. Instead of controlling the
fraction of messages to drop, it controls the maximum frequency to send
the signal (in Hz).
Update docs and bump to v5.0-dev because of API change.
Move internal fields lower in CanSignal struct so they can be defaulted.

While we're already changing this API, I'd like to take care of this as
well - nobody should be defining values for the received, lastValue or
lastSendTime field, so those should be after any user-controllable
fields (like writeable and states).
Don't normally log bus and I/O stats when in debug mode.
Remove a resolved TODO.