reimplement with Array.Copy

[todo]

las-cs/src/LasCs.cs

Lines 173 to 178 in 0463e60

	// TODO: reimplement with Array.Copy
	public static T[][] chunk<T>(T[] arr, int size)
	{
	int i = 0;
	return arr.GroupBy(s => i++ / size).Select(g => g.ToArray()).ToArray();
	}

---

This issue was generated by todo based on a TODO comment in 0463e60 when #2 was merged. cc @laslibs.

[iykekings]

A very helpful resource -> https://stackoverflow.com/questions/11207526/best-way-to-split-an-array