Introduces:
- config::Unit: base class for physical quantities
- motion::AxisUnit: type-checked steps type
"config/unit.h" defines basic physical quantities, which are not
normally used elsewhere besides config.h.
"modules/axisunit.h" extends the modules::motion namespace with
Axis-aware units, with one type per axis per unit.
P_pos_t defines step positions for the pulley, I_pos_t for the idler,
etc. These are defined through the literar operators which are
similarly named and automatically convert a physical quantity to an
AxisUnit at compile time:
P_pos_t pulley_pos = 10.0_P_mm;
Besides type-checking, AxisUnit are otherwise identical to raw step
counts and are intended to be used along with the updated Motion API.
PlanMove/PlanMoveTo has been extended to support moves using these units
or physical quantities. Again, conversion is performed at compile time.
Yuri D'Elia