Chebyshev to Gegenbauer Conversion

Converts Chebyshev polynomials to Gegenbauer polynomials.

Given a series of expansion coefficients in terms of Chebyshev polynomials, this script finds the corresponding Gegenbauer (Ultraspherical)coefficients for the same function. Useful for spectral methods. This is a generalization on the Chebyshev-Legendre conversions.