tools: reduce diff noise with GtkRadiant

This a MR to reduce diff noise between NetRadiant and GtkRadiant in the tools tree.

There is full of slightly minor change like whitespaces or newlines or headers or sometime just another way to do things because two people fixed the same issue at the same time on both side and they just not written the same line in the same order. All of this makes cherry-picking across forks annoying because it raises stupid merge conflict about things that are not meaningful.

Hence this Merge Request.

I also imported two fixes from GtkRadiant side.