Conformal mapping example

This adds an example that computes a conformal mapping with the Theodorsen integral equation, a nonlinear integral equation for the boundary correspondence of the Riemann mapping function f: D \to \mathbb{C} for a nearly circular target domain, where D is the unit disk. The equation is solved with an iterative method using an FFT. pyfmmlib is used to efficiently evaluate the Cauchy integral formula with the FMM after obtaining the boundary correspondence.