Issues with Windows build

Hello, I managed to get a converted model working using a Linux VM, but found two issues with the `0.2.6` .exe file when I tried doing the same thing in Windows 10:
1. No error messages shown when exceptions are thrown. To reproduce, download birealnet18.onnx and run `onnx2bnn.exe birealnet18.onnx sample.dab --binary-convs 9000,`
2. Converted models did not have the correct version number and thus could not be loaded into the Android app. To reproduce, run `onnx2bnn.exe birealnet18.onnx sample.dab --aggressive` and import sample.dab into the daBNN-example repository. An error message along the lines of `E/libc++abi: terminating with uncaught exception of type std::runtime_error: model_->version() == 2 is not satisfied! The model version should be 2, got 2950774155 instead.` should be shown in ADB Logcat.

Start by reproducing both commands on Windows 10 with birealnet18.onnx, then compare the executable's exception output and generated model version with the Android app's expectations. Check the imported sample.dab in the daBNN-example repository and ADB Logcat; done means exceptions are visible and the converted model reports version 2 and loads successfully.

Written by the indexing model from the issue text.