This will be a total recode of the bamboo logic.

Bamboo shoots should be planted like a sapling. The shoot when bonemealed will grow in to a full sized bamboo 'tree'. If a bamboo shoot is planted and not bonemealed it will naturally turn in to a single bamboo block that will proceed to grow like sugarcane over time up to 10 blocks or some sutch.

This will mitigate all the confusing logic bamboo has atm (sorry @chylex - too many complaints).

Bamboo will still generate in the world naturally in patches.
A new json for the bamboo block has already been created so this shouldn't take an age to do...

Done.