Working on BeatSaber 1.17.0

Changes

• New filter methods: Unplayed, Played (thanks @ChrisJAllan ).
• Now using IPA Config (no more XML settings file).

Fixes

• #166 : Do not traceback and break the song list when filtering by Ranked and ranked data is unavailable.
• Missing empty prefab for songs, caused the song list to load poorly in some scenarios.
• Double filtering no longer overwrites the original song list.