Changes to reduce incidence of false heating fault alarms, in particular
"temperature rising much more slowly than the expected 0.0C"
Stepper drivers beyond the first 5 are assumes to be non-TMC2660 drivers
Increased max number of probe points to 64 on Duet WiFi and 32 on Duet
0.6/0.8.5
Corrected M37 reporting of simulation time
Added move debug facility
Added recording of more types of move underrun
Use fabsf instead of fabs
M21 doesn't re-mounjt a drive that is aloready mounted and has open
files on it
Added "volumes" variable in extended status report
Report card details after M21 is called
Bug fix: M220 speed changes were nott being implemented as soon as they
should be
Bug fix: lookahead was sometimes failing to join sequences of short
decelerating moves together
Bug fix: at startup the thermistor readings were sometimes very high,
which triggered a bug in strtod() called in PanelDue firmware 1.14 and
earlier
