Screen preflet overwrites ~/config/settings/kernel/driver/vesa even if file is read only.

[bipolar]

While testing the BIOS patching feature of the VESA driver (that requires adding bios_patching true to the vesa setting file) noticed that changing resolutions via the Screen preflet re-writes the file regardless of its read-only status.

Problem is... Screen preflet only adds the "mode <width> <height> <depth>" line, but "removes" the rest.

Not sure if it makes sense to make Screen load the existing file and change only the mode line, but at the very least it should warn the user before overwriting the file.