Blocks store their initial biome coloring

The point of this suggestion is to allow the player more freedom in controlling biome coloring in their builds.

When a block is "generated" within a biome (for example, a tree is grown from a sapling and generates leaves, or a dirt block is converted to grass by growth) it should note the biome it generated in and store this information when broken by the player. This way, blocks placed in other biomes will retain the coloring of their first biome.

This will allow the player to, for example, build an oasis in a desert without its grass or leaves going brown, assuming the grass and leaves were obtained in a more lush biome. Patches of river biome grass may be removed from another biome, should the player choose.

A few other points relating to this idea:

• Collection of blocks with this data may be limited to tools with Silk Touch.
• Grass "generation" should depend on the type of grass it spreads from, rather than the biome of its column.
• It is possible to allow the player to change the biome of a column, depending on the biome-colored blocks it contains. Allowing this would remove a limitation to the player's influence on the world, now only being unable to affect regions set by generated structures.
• A consequence of this idea is that sheep can spread biome coloring by eating grass at a biome's edge. A method to avoid this is to have dirt retain the biome of the grass that was eaten, and override the new biome when it reconverts to grass.