Scaling nuke

This commit introduces new textures and a bit of code so that the nuke targeting reticle scales dynamically according to the unit. It correctly shows inner and outer radius, so it's much better for aiming. It looks as close to the current one as possible (Colour, design etc) but it scales now.
This should likeliky be a nil check for it to work right.

In lua we can do:
```if not InnerSize or not OuterSize then ...```

Which reads a bit better, too :)