Multinode support improvement ideas

[SwissalpS]

3b7db12 keeps servers from crashing when a multinode-node is clicked in the 'wrong' corner. Possibly there is a way to recalculate the origin or even find positions with the size of the node in mind.

I currently don't have much motivation for that though. The tool is called node replacement tool not multinode replacement tool.

Just in case somebody does want to pick this up at some point. The mode that triggered above mentioned crash was 2.3 (field, rotation only) and the node being used was a bridger:medium__upper_chord_white.
To reproduce the crash prior to 3b7db12, you'll need to try clicking on different areas of the node.

[SwissalpS]

{
	name = "replacer:replacer_technic",
	metadata = "",
	count = 1,
	meta = {
		mode = "2.3",
		description = "\27(T@replacer)Node replacement tool (technic)\27E\
(79 21) bridger:medium_upper_chord_white\
White Medium Upper Chord",
		replacer = "bridger:medium_upper_chord_white 79 21",
		color = "#10bb68"
	},
	wear = 853
}