Cleanup and fixup

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`.

worldedit/common.lua

@@ -0,0 +1,114 @@
+--- Common functions [INTERNAL].  All of these functions are internal!
+-- @module worldedit.common
+
+--- Copies and modifies positions `pos1` and `pos2` so that each component of
+-- `pos1` is less than or equal to the corresponding component of `pos2`.
+-- Returns the new positions.
+function worldedit.sort_pos(pos1, pos2)
+	pos1 = {x=pos1.x, y=pos1.y, z=pos1.z}
+	pos2 = {x=pos2.x, y=pos2.y, z=pos2.z}
+	if pos1.x > pos2.x then
+		pos2.x, pos1.x = pos1.x, pos2.x
+	end
+	if pos1.y > pos2.y then
+		pos2.y, pos1.y = pos1.y, pos2.y
+	end
+	if pos1.z > pos2.z then
+		pos2.z, pos1.z = pos1.z, pos2.z
+	end
+	return pos1, pos2
+end
+
+
+--- Determines the volume of the region defined by positions `pos1` and `pos2`.
+-- @return The volume.
+function worldedit.volume(pos1, pos2)
+	local pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	return (pos2.x - pos1.x + 1) *
+		(pos2.y - pos1.y + 1) *
+		(pos2.z - pos1.z + 1)
+end
+
+
+--- Gets other axes given an axis.
+-- @raise Axis must be x, y, or z!
+function worldedit.get_axis_others(axis)
+	if axis == "x" then
+		return "y", "z"
+	elseif axis == "y" then
+		return "x", "z"
+	elseif axis == "z" then
+		return "x", "y"
+	else
+		error("Axis must be x, y, or z!")
+	end
+end
+
+
+function worldedit.keep_loaded(pos1, pos2)
+	local manip = minetest.get_voxel_manip()
+	manip:read_from_map(pos1, pos2)
+end
+
+
+local mh = {}
+worldedit.manip_helpers = mh
+
+
+--- Generates an empty VoxelManip data table for an area.
+-- @return The empty data table.
+function mh.get_empty_data(area)
+	-- Fill emerged area with ignore so that blocks in the area that are
+	-- only partially modified aren't overwriten.
+	local data = {}
+	local c_ignore = minetest.get_content_id("ignore")
+	for i = 1, worldedit.volume(area.MinEdge, area.MaxEdge) do
+		data[i] = c_ignore
+	end
+	return data
+end
+
+
+function mh.init(pos1, pos2)
+	local manip = minetest.get_voxel_manip()
+	local emerged_pos1, emerged_pos2 = manip:read_from_map(pos1, pos2)
+	local area = VoxelArea:new({MinEdge=emerged_pos1, MaxEdge=emerged_pos2})
+	return manip, area
+end
+
+
+function mh.init_radius(pos, radius)
+	local pos1 = vector.subtract(pos, radius)
+	local pos2 = vector.add(pos, radius)
+	return mh.init(pos1, pos2)
+end
+
+
+function mh.init_axis_radius(base_pos, axis, radius)
+	return mh.init_axis_radius_length(base_pos, axis, radius, radius)
+end
+
+
+function mh.init_axis_radius_length(base_pos, axis, radius, length)
+	local other1, other2 = worldedit.get_axis_others(axis)
+	local pos1 = {
+		[axis]   = base_pos[axis],
+		[other1] = base_pos[other1] - radius,
+		[other2] = base_pos[other2] - radius
+	}
+	local pos2 = {
+		[axis]   = base_pos[axis] + length,
+		[other1] = base_pos[other1] + radius,
+		[other2] = base_pos[other2] + radius
+	}
+	return mh.init(pos1, pos2)
+end
+
+
+function mh.finish(manip, data)
+	-- Update map
+	manip:set_data(data)
+	manip:write_to_map()
+	manip:update_map()
+end
+