Luminous Sand, Gravel, Redsand

This idea is to add three new light-emitting gravity-affected blocks.

They are:

Luminous Sand, crafted from one Sand surrounded by four Glowstone dust,

Luminous Gravel, crafted from one Gravel surrounded by four Glowstone dust, and

Luminous Red Sand, crafted from one Red Sand surrounded by four Glowstone dust.

Each of them gives off a block light level of eight.