Paint's Dynamic Lighting

Changes since v1.1:

* Accommodation for multiple players using these features in the same area.

* I don't know why, but holding dimmer lights are more laggy. As a result, I've removed holding magma blocks giving light level 3 as the lag they caused outweighed their usefulness.

* Holding two light sources at the same time is now supported. The one with the greater light level will provide light.

You'd be better off using a mod that does this, if you are able.