The change-playlist function relied on toggling shuffle to restart playing which is no longer the case, so always handle it when changing playlist instead.
This simplifies processing nwidget parts as, unlike the remaining length, the pointer to the end of the list never changes. This is the same principle as we use(d) for tracking end instead of length for C-style strings.
And this removes 160~ instances of the lengthof() macro.
This to prevent compilation issues between runs with and without precompiled
headers. Also remove the headers from the rest of the code base as they are
not needed there anymore, although they do relatively little harm.
The music-set does not need to be selected for this to occur.
Resolved by using std::string instead of fixed buffer for song names,
which avoids manual string copying and removes the length limit.
DropDownListItem are strongly managed using std::unique_ptr to ensure leak-free handling. Appropriate use
of move-semantics make intent a lot clearer than parameter comments and allows the compiler to generate
copy-free code for most situations.
Rewrite of almost the entire music control logic to a more modern style, hopefully also easier to understand. The old playlist handling made it look like arcane magic, which it doesn't have to be.
- Playlists are now stored in std::vector of objects instead of arrays of bytes with magic sentinel values, that need to be rotated around all the time. Position in playlist is stored as a simple index.
- The theme song is now reserved for the title screen, it doesn't play on any of the standard playlists, but is still available for use on custom playlists.
- When the player enters/leaves the game from the main menu, the music always restarts.
- Playback state (playing or not) is kept even if music becomes unavailable due to an empty playlist (or an empty music set), so it can restart immediately if music becomes available again.
- The shuffle algorithm was changed to a standard Fisher-Yates.
- Possibly better behavior when editing a custom playlist while it's playing.
- Custom playlists should be compatible.
- Framework for supporting custom playlists with songs from multiple music sets.
Tested with various languages and GUI font sizes, should look good everywhere.
Also clamps near-end values to minimum and maximum so 0 and 127 are possible to achieve even on small GUI sizes (like the default.)
