Use 'wget -c ...' to allow wget to resume interrupted downloads

[lutusp]

Please change https://github.com/Stability-AI/StableCascade/blob/master/models/download_models.sh to allow 'wget' to detect files that have already been fully or partly downloaded -- IOW change each 'wget' to 'wget -c'. This prevents a long re-download by people who may already have some required files downloaded, or whose prior download was interrupted.

This is an otherwise harmless change. It detects whether a file is already present before overwriting an existing file, and continues an interrupted download if for any reason a prior download is interrupted. Those of us with dodgy Internet connections need this feature.

[shreyash-Pandey-Katni]

Hi Team, May I take it up?