design decision: exclude or include high in ranges?

[pyropeter]

Currently, chunkCreateBatch excludes the high point from the cuboid, but Chunk.high is included in the cuboid.
This is very misleading.

[pyropeter]

Imho, Chunk.high should not be part of the cuboid. The advantages are as follows:

• Easy calculation of the number of Blocks in a Chunk ((high.x - low.x) * (high.y - low.y) * (high.z - low.z))
• Common surface of two adjacent Chunks can be found easier (if (a->high.x == b->low.x) {// common YZ-surface})

A change would require quite a lot of nontrivial changes in chunkgen.c. The other parts of the code should be easy to migrate. It is probably best if this waits until chunkgen.c gets rewritten.