add scale_channels, swish, logistic(sigmoid), avgpool ; add enet_coco(EfficientNetB0-Yolov3).cfg

[thnkinbtfly]

Added Features

Add followings:

1. [scale_channels] layer with scale_wh=0
2. swish and logistic activation functions
3. [avgpool] layer, which is global average pool in darknet

Tested with enet_coco (I removed dropout layers from the original enet_coco.cfg)

Reproduce test with enet_coco

1. git clone the tkDNN forked darknet.

2. git apply following patch file to the forked darknet. Note that if you don't change the BN epsilon (#167), the final output will fail to be similar.

   diff --git a/src/blas.c b/src/blas.c
   index 7bfc752..8d3ddd8 100644
   --- a/src/blas.c
   +++ b/src/blas.c
   @@ -289,7 +289,7 @@ void normalize_cpu(float *x, float *mean, float *variance, int batch, int filter
        for(f = 0; f < filters; ++f){
            for(i = 0; i < spatial; ++i){
                int index = b*filters*spatial + f*spatial + i;
   -                x[index] = (x[index] - mean[f])/(sqrt(variance[f] + .000001f));
   +                x[index] = (x[index] - mean[f])/(sqrt(variance[f] + .00001f));
            }
        }
    }
   diff --git a/src/darknet.c b/src/darknet.c
   index f7d6a81..21b0f83 100644
   --- a/src/darknet.c
   +++ b/src/darknet.c
   @@ -506,6 +506,9 @@ void run_export(char *cfgfile, char *weightfile, char *out)
        } else if(l.type == SHORTCUT) {
            printf("export SHORTCUT\n");
            // no weights
   +        } else if(l.type == SCALE_CHANNELS) {
   +            printf("export SCALE_CHANNELS\n");
   +            // no weights
        } else if(l.type == ROUTE) {
            printf("export ROUTE\n");
            // no weights
   @@ -515,6 +518,9 @@ void run_export(char *cfgfile, char *weightfile, char *out)
        } else if(l.type == MAXPOOL) {
            printf("export MAXPOOL\n");
            // no weights 
   +        } else if(l.type == AVGPOOL) {
   +            printf("export AVGPOOL\n");
   +            // no weights
        } else if(l.type == REORG || l.type == REORG_OLD) {
            printf("export REORG\n");
            // no weights          

3. download enet-coco weights from official darknet repo

4. follow the steps to generate weights and input/outputs. Example : ./darknet export ../tkDNN/tests/darknet/cfg/enet-coco-wo-dropout.cfg enetb0-coco_final.weights layers

5. build tkDNN and

   cd build
   mkdir enet_coco_wo_dropout
   cp -r ../../darknet/layers enet_coco_wo_dropout/ && cp -r ../../darknet/debug enet_coco_wo_dropout
   ./test_enet_coco_wo_dropout