Handful of small fixes.
* Fix material loading from config requiring minecraft: namespace.
* Fix disallowed-lightning blocks. Lightning entities are weird.
* Fix /wg reload overwriting config changes.
* General around thread usage/naming/shutdown. If anyone was actually
making their own managers/indices you deserve to break.
(3468e3d4 by wizjany)
Add option for resetting fall distance when void falling teleport is on.
reset-fall-on-void-teleport, defaults to false. (I can't remember if
old WG 6 behavior was to do this or not...?)
(afe042ef by wizjany)
