AbstractShapeParameterization

[lstagner]

So right now we have standard shape parameterization for the boundary conditions of the Solov'ev Equilibrium

x = R0*(1 + epsilon*cos(tau + asin(delta)*sin(tau)))
y = R0*(epsilon*kappa*sing(tau)

where epsilon is the inverse aspect ratio, delta is the triangularity, kappa is the elongation, and tau = (0, 2pi). But there are other shape parameterizations we can use such as the ones proposed by Luce and others.

I suggest creating a new type AbstractShapeParameterization where we can define new shapes. The type would be callable S(tau) - (x,y)