New event on_entity_color_changed

[Xorimuth]

I'm currently having to use `on_gui_closed` for this one, but it only takes effect when the overall GUI is closed, not immediately.

Why? I'm kind of trying to re-create the line on the ground from a spidertron to its destination, which is coloured the same colour as the spidertron. I can't detect the colour changing in order to change the colours of my LuaRendering lines.

Alternative name: on_entity_recolored

[Bilka]

Hello, this was added at some point: https://lua-api.factorio.com/latest/eve ... or_changed