GitLab

* update subgraph.

* update subgraph API.

* keep node embedding.

Conflicts:
	python/dgl/graph.py

* support multiple fields in spmv

* finishing SPMV executor

* non-spmv case

* refactor code to give single mfunc rfunc a shortcut

* two test cases to test multiple msg/red func

* catching cases where msg uses anonymous field

* default ALL for update edge

* more corner case test

* print failed test

* delete print

* fix builtin max reducer