Small change to scavengers plugin

Mention who starts/ends/resets
Gen 4: Leaf Guard does not prevent Rest
Salamence goes back to BL
Remove beta from gen 4 tiers
Added Arceus aliases based on plates

Flyceus = Arceus-Flying etc.
Merge pull request #971 from CrestfallPS/patch-18

Added Arceus aliases based on plates
minor update
Merge remote-tracking branch 'upstream/master'