Add option to permanently allow scripts only for specific files.

It's rather irritating to have to manually enable scripts any time I open a file that has, e.g., python-based drivers. The only alternatives, however, are to either permanently allow scripts for all files, which is a security risk, or to open the file through the file browser and check the "trusted source" box, which is even more tedious. It would be nice to be able to mark a specific file as a trusted source and have that persist between sessions.