Ultimately they should be unnecessary now that upstream's fix has been
in place for a while. Removing this reduces our own footprint, and gets
rid of any possible unintended behavior.
Makes Auto Save Rate setting configurable per-world. If the auto save rate is left -1, the global bukkit.yml value will be used.
Process auto save every tick instead of once per auto tick interval, so that chunk saves will distribute over many ticks instead of all at once.
Re-introduce a cap per tick for auto save (Spigot disabled the vanilla cap) and make it configurable.