Hardcore and creative respawn at death location w/ keep inventory

Death in Hardcore mode should respawn (as a spectator) right next to where you died, instead of at your spawnpoint, so that the player can immediately reflect on their world's progress, instead of having to go find where they died first. Also, spectators should be able to go into and out of portals to further see their progress.

Players in creative mode should automatically have "Keep Inventory" on. This is mostly for new players, so that if they fall into the void, etc. they don't have to recreate their creative inventory.