Coil forces not properly calculated for circuit coils

[gsrutherford]

I have two versions of my device, one using circuits and one not. They produce very different values of coil forces.
I have narrowed this down due to line 181 of coil.py not being sufficient to set coil's current to zero.

This is because Circuit.Br resets the coil's current to a nonzero value.

Example:
My non-circuit code produces a radial force of -75.68 MN while the circuit code gives 57.51 MN for a certain coil.
If I do out the math in the coil.getForces method in my non-circuit version without setting coil.current = 0, I get 57.51. When I do set coil.current = 0, I get -75.68.

Suggestion:
In Circuit.getForces, set the multiplier of the coil in question to 0 prior to getting that coil's force and then set it back to the original value afterwards.