GitLab

* Add row/col sorted flags

* improve sorting paths

* Remove print statement

* Keep track of sorted matrices

* Remove sort check in to_block

* Improve CPU sorted COO->CSR

* Handle the zero edge case

* Remove omp default clause to work with MSVC

* Update comments on sorted COO->CSR cpu implementatoin

* Expose sorted to python interface

* Make check_sorted default to false for dgl.graph()

* remove check sorted; add utests

* remove check_sorted flag
Co-authored-by: Minjie Wang <wmjlyjemaine@gmail.com>