Allow Unicode in high score list

[davidjoffe]

https://github.com/davidjoffe/dave_gnukem/issues/148#issuecomment-1327738959

[This stuff relates to the new 'unstable/dev' stuff that's not yet enabled in the core stable codebase and would require addition of a few new dependencies and some new (open-enough license-based) datafiles for eg ttf or otf] This relates to these, see for details: https://github.com/davidjoffe/dave_gnukem/issues/178 https://github.com/davidjoffe/dave_gnukem/issues/148

[davidjoffe]

This is now partially done, it's now technically possible to enter Unicode in high score lists (but more complex languages like Arabic that require .ttf won't work, and it's still limited by the current new small pixeloperator font in terms of display, unless one builds with .ttf enabled, but it works) - but it could use more testing on all platforms, and we need more fonts etc. (more raster fonts, and/or ttf etc.) - ttf support is in the code in 'beta' but not yet enabled (it would add a dependency so hesitant to add it yet, due to all existing packages) - but the hiscore file now loads/saves as utf8.