Add Fit Screen option to resolution settings

There may be times where users want to have the desktop resolution match the device resolution
on a small screen. The change adds the option without changing existing functionality of the
automatic resolution setting.

Also included localized text strings for the new option and addressed some issues with string
comparison in non en-US locales.

I'm not completely sure about the correctness of adding the context to GlobalSettings, but it seemed the least disruptive way to fix the localization issues I encountered in testing.