Ninja-night vision now works.

A ninja now uses proper glasses instead of using its own hack.
Fixed a bug that would override the old ninja-night vision unless one also wore additional glasses in the glasses-inventory slot.
Adds overlays to thermals and mesons as well. Slightly reduces the intensity of the night vision overlay.
Merge pull request #6318 from PsiOmegaDelta/EyeOfTheNinja

Ninja-night vision now works.