New classes that generates quadratures for numerical integration.

Chebyshev A: Chebyshev quadrature for computing the integral \int_{-1}^1 dx f(x)sqrt(1-x^2);
Chebyshev B: Chebyshev quadrature for computing the integral \int_{-1}^1 dx f(x)/sqrt(1-x^2);
GLSeSt: Different (more precise?) method for computing GL weights.