Use UTF-8 for Linux

[zeule]

The wchar_t in Linux is very wide, 32 bits, and thus almost unused,
which, in turn, results in poor support in tooling. And that's to be
expected when UTF-8 is the default. At the same time, Iconv, which is
part of glibc, is universally available. Thus we can use it to convert
UCS-2 into UTF-8 in Linux and always use UTF-8 in the library API.

[zeule]

@hzdbyte, which other project do I have to adapt to merge in this change? Only the bundled GUI, or qgen as well, for example?

[hzdbyte]

To be honest I don't really like using iconv as dependency.
The library doesn't strictly depend on wchar_t since it has it's own string processing implementation, thus it can use any type of strings. I'd still prefer to keep the internal string representation based on fixed length type (it can be "short"/2bytes for example). We can implement UTF8 support in the special version of bindings to be used by clients/players with UTF8 strings (that'd be next to the "default" one).

[zeule]

But Iconv is a part of glibc, thus it brings no new dependency package-wise. Utf8 is the standard for Linux locales. Can that change your attitude?

[hzdbyte]

Wouldn't it be better to create utf8 binding that'd convert strings back and forth for utf8 players?

[ghost]

It would be nice if in general when a game is ingested it is converted to utf-8 always, since that is most sane. I am still learning about QSP and it isn't super clear to me yet, but that would be a good default.