* remove edge and to bipartite and graphsage with sampling
* fixes
* fixes
* fixes
* reenable multigpu training
* fixes
* compatibility in DGLGraph
* rename to compact_as_bipartite
* bugfix
* lint
* add offline inference
* skip GPU tests
* fix
* addresses comments
* fix
* fix
* fix
* more tests
* more docs and unit tests
* workaround for empty slice on empty data
* [WIP] PinSAGE operators
* moved the edge remapping mess into C
* some docstrings
* lint
* lint x2
* lint x3
* skip gpu test on topk
* extend pinsage to any metapath
* lint x4
* addresses #1265
* add always_preserve (fixes#1266) and fix a silly bug
* disable gpu test on compaction
* lint
* fix a horrible bug and add more tests
* lint
* addresses comments
* lint
* bugfix
* addresses comments
Co-authored-by: Minjie Wang <minjie.wang@nyu.edu>