Stepconf blindly accepts step rates that are too high

On the second page, stepconf shows a "maximum step rate" value which is calculated based on latency and step timings. On the axis pages, a step rate for each axis is computed based on the stepping parameters and max speed entered. stepconf could, but does not, check that the axis step rates are lower than the "maximum step rate". Instead, the only indication of misconfiguration is when emc is run and the user encounters joint following error messages.