added a set version for the evaluation of the hessians
added method to print sparsity patterns; new optional argument added to hessian sparsity evaluation functions
added method to print sparsity patterns for vector<set>
added support for custom jacobian and hessian sparsities in atomic functions;
added some caching of sparsity information in CGAtomicFunBridge;
the generated reverseTwo functions save hessian rows instead of columns;