Set SDL_HINT_APP_NAME for tiles

[DeeUnderscore]

Summary

None

Purpose of change

Make SDL properly identify the game. Specifically, under Linux, identify CDDA when requesting the screensaver inhibited via dbus (since SDL inhibits screensaver by default since 2.0.2, CDDA currently does this without providing a name, so it shows up as "My SDL application"), and identify CDDA under audio mixers.

I encountered this, because the power management widget under KDE Plasma kept telling me "My SDL Application" is blocking sleep and screen locking.

Describe the solution

Under SDL2, this can be done with SDL_APP_NAME, as documented by SDL. This appears to be best set before SDL_Init().

Describe alternatives you've considered

This could be gated to Linux, as it does not seem to affect other platforms, but SDL documentation indicates that on platforms where it's unsupported, it does nothing.

It could also reuse the window title, but in the contexts it appears, it's better without the version string.

Testing

Built CDDA with the changes, and verified that the name shows up where it should.

Additional context

Plasma power widget showing name:

Plasma volume slider with the name:

[DeeUnderscore]

Whoops, noticed some spurious whitespace in the diff.