Change valve, gpi, gcc, pip setpoint hysteresis to a percentage of the protection/atvac setpoint

[slacAdpai]

Currently the hysteresis setpoint and protection/atvac setpoints can vary greatly. The VGC setpoint hysteresis is a little smarter and does not allow the hysterisis setpoint be above the atvac setpoint/protection. A more intuitive design would be to set the hysteresis to be a percentage of the protection/atvac setpoint.

Bill and I were getting confused when changing the setpoint hysteresis did not change it because the protection/atvac setpoint was below the hysteresis.

[ghalym]

Good point. Will work on that.

[slacAdpai]

A good starting point is VGC. You already have half of it done there.