Rearranged CRSSparsityInternal to avoid initialization confusion, #575
Concerning #575: Debugged sparsity pattern caching. Now works but segfault occurs at program closure.
automatic documentation update
Concerning #575: Refactored sparsity pattern caching. Now working, but still not enabled.
Refactored sp_diag to allow caching
Fixes #575. Enabled sparsity pattern caching