The playlist macros set the music list twice, once before the
story screen and again in prestart, but the order of tracks is different.
This means that the track order at the titlescreen and in the lobby is now the same
as the track order in a scenario using the default playlist, which previously was not the case.
Similarly, the track order in the editor is now the same as the track order
in a scenario using the full playlist.
Whether that actually matters? I have no idea. I doubt it.
In any case, as of this commit, there are no schema validation errors
at the title screen, when entering the MP Create screen, or in the map editor.
...by moving them to a separate subdirectory, renamed
editor2_tool_hint tag (dropped the "2"), added background music
playlist tag for the editor (FR / bug #11407)
