Important rendering bugfix: Light components (TCastlePointLight and TCastleSpotLight)

[DP News-Robot]

Sorry for the long news title and even longer news post ? This is a very important bugfix and at the same time it couldn’t (reasonably) have been done in 100% backward-compatible way. We tried to explain everything below. If in doubt how to upgrade your projects (in case things will look different), don’t hesitate …