Changes including SDP class
Changes including SDP class

Differentiating with respect to z directly turns out to be slow. This
adds rules for converting rho derivatives into z derivatives. Also added
is an SDP class for storing a convolved conformal block table.

Signed-off-by: Connor Behan <89f96a099c47edae2e9c5a371cbf43991ac7aa8c@gmail.com>

cbehan/pycftboot