Generalise lead configurations to arbitrary angles
It is possible to generalise lead configurations to arbitrary angles, instead of clunky up/down/left/right options. User could specify the lead rotation angle with respect to the origin, which would serve as the gauge_angle variable (e.g. check implementation of FiniteHarmonicLead). Gauge transformation has already been defined in terms of arbitrary angle, so all that needs to be done is coordinate rotation of the leads by the same angle.