Lyric engine overhaul
Lyric engine overhaul

Highlighting lyrics is now far faster due to:
- direct reference from lyric to its own html element
- activeness is kept within lyric element itself

Other misc changes:
- each state.slots/lyrics is now their own element with the
song.slotsBase/lyricsBase as prototype
- reverseMapping to correlate between lyrics and slots

EaterOA/GanbaWhoby,EaterOA/GanbaWhoby