Version 0.2.4

This release includes two major performance improvements to the sparse-direct LDL factorizations and DPP sampling: (1) Simplicial, up-looking factorizations are now automatically used for small and/or low-intensity factorizations, leading to orders of magnitude speedups on some matrices, and (2) Nested OpenMP tasking now terminates based upon the workload of the subtree rather than its depth. It also contains sequential and DAG-scheduled dense, non-Hermitian DPP samplers and a routine for a posteriori computation of the likelihood of dense and sparse DPP samples. The factorizations and DPP sampling can now also be instrumented -- via the -Denable_timers=true configuration option -- to output a Graphviz visualization of the inclusive and exclusive processing times at the top of the supernodal assembly tree. And example drivers were added for sampling and visualizing -- via ASCII and/or TIFF -- uniform domino tilings of the Aztec diamond and uniform spanning trees from Z^3 or a hexagonal tiling of the plane.