Use new BiRefNet with massive training and IoU fine-tuning.

app.py

@@ -41,7 +41,7 @@ class ImagePreprocessor():
 
 
 model = BiRefNet(bb_pretrained=False)
-state_dict = ['./BiRefNet_ep580.pth', 'BiRefNet-massive-epoch_240.pth'][-1]
+state_dict = ['./BiRefNet_ep590.pth', 'BiRefNet-massive-epoch_240.pth', 'BiRefNet-massive-epoch_300.pth'][-1]
 if os.path.exists(state_dict):
     birefnet_dict = torch.load(state_dict, map_location="cpu")
     unwanted_prefix = '_orig_mod.'