add fcos backbone

yolo/models/fcos/fcos_backbone.py

@@ -7,7 +7,7 @@ except:
     from  resnet import build_resnet
 
 
-# --------------------- Yolov1's Backbone -----------------------
+# --------------------- FCOS's Backbone -----------------------
 class FcosBackbone(nn.Module):
     def __init__(self, cfg):
         super().__init__()

yolo/models/yolov5/modules.py

@@ -73,4 +73,3 @@ class CSPBlock(nn.Module):
         out = self.conv_layer_3(torch.cat([x1, x2], dim=1))
 
         return out
-