parametric settings

[bobpellegrino]

For certain settings like cooling behavior or bridging, it would be helpful to specify the settings parametrically. Instead of discreet values like "For layers under 20 seconds, set the speed to 50%", set the speed of the extruder or the fan speed according to the actual layer time. So if the trigger value is 20 seconds, it would decrease the value by 5% for every second under 20 seconds. You might want to parameterize extruder temperature as well.