Spawner Minecarts - feature update

[TheThanathor]

Updates (or rather removes) features from Spawner Minecarts.

• Removed any fueling of Spawner Minecarts (no more flowers etc)
• Every Spawner Minecart within a 9x8x9 area of another now reduces the spawn rate, at least 4 other Spawner Minecarts reduce it to 0 (subject to change)
• Spawner Minecarts accept any spawner, unless it's a smithed block or a mob inside the spawner data has gm4_spawner_minecarts:{ban_pickup:1}

[BPR02]

Yeah this looks good. I think the nearby spawner minecart check solves the balancing issue in an elegant and simple way. No more hyper spawners from infinitely stacked minecarts in a single block and no more complicated rules to keep the minecart running. Plus with the player required radius, it means there is a finite amount of spawner minecarts a single player can load. Maybe we could make spawner minecarts slower than normal spawners (i.e. increased delay) if we wanna keep a "running cost" instead of allowing spawners to be moved with no downside at all.