Support for GroupConv

[Yuzz1020]

Hey, @han-cai , thank you so much for the release of code. But I notice that the current version only supports for the normal convolution, when the initial architecture involves GroupConv, the code doesn't work.

As you mentioned in the paper, this code should support GroupConv and I really want to try this function. Could you please update the code to the newest version with support of GroupConv?

Thanks a lot!