Updated numerically-typed CSCMatrixOps
moved sciss ref to right place, removed unused imports
weird merge.. moved too many things around..
Merge pull request #291 from gabeos/feature/algebra

Feature/algebra
fork when we run tests, to prevent oom errors
convert for Complex numbers
more tests for CSCMatrix, caught 1 bug
made registration work for axpy/SV/DV
move test coverage. good enough
little more coverage