Precision issue under large coordinates with /cglow block

[Xenapte]

/cglow block uses 32-bit floats, which causes noticeable precision issue when coordinates are high enough. This is actually quite similar to vanilla Minecraft before Beta 1.8.

[Earthcomputer]

Hmm, floats are only supposed to be used as coordinates relative to the camera, but they're clearly being used elsewhere

[xpple]

Relates to #268. I don't remember why that issue was closed but assumingly because it was supposed to be fixed.