When setting region cube, make sure player has not set two positions very far apart.
This can happen when player has been editing one part of the map, then travels to a distant part of the map and tries to start setting a new region.
This does not affect the ability to operate on large areas, nor the setting of the markers, just the region cube marking.
Non-stylistic changes:
* Add LuaDoc/LDoc support.
* Fix `clear_objects` area size calculation.
* Fix `clear_objects` removing player objects.
* Fix shadowing of marker entity name with player name.
* Make visualization functions use `swap_node`.
* Make hidden nodes unwalkable.
* Prevent `hide` from hiding air.
* Make deprecated functions log to deprecated stream when called.
* Fixed `replaceinverse` not using normalized node names.
* Added .gitignore.
* Bump version to 1.1.
Stylistic changes:
* Change `x = function` to `function x`.
* Change comment format.
* Make missing VoxelManip error less obnoxious.
* Move `sort_pos` into `common.lua`, which is a required module.
* Remove local copies of `minetest`.
* Remove `worldedit = worldedit or {}` from modules.
* Replace replaceinverse with an inverse argument to `replace`.
* Added `error()`s on on invalid axes.
* Change `wip` to `TODO`.
* Rename `clearobjects` to `clear_objects`.
* Remove `hollow_{sphere,dome,cylinder}` and replace them with a hollow parameter to each function.
* Add helpers to reduce code duplication.
* Renamed `Chat Commands.md` to `ChatCommands.md`.
