#16 Add a way of forcing 128K .sna files to load in 128K mode

[Joerg Pleumann]

When loading a 128 .sna file Fuse does that in Pentagon mode by default even if I don't have the ROMs installed. Could the latter be taken as a hint that I am not interested in Pentagon support? Or, alternatively, could there be an override checkbox in the settings that forces 128K .sna files to be loaded with the selected machine?

(Let me know if this is a request that should actually be sent to a more upstream project, but Fuse for MacOS is my main contact point, so I thought I'd start here.)