Fixes for gamebreaking metabolism rates

- A single chili doesn't kill anymore
- Chloral hydrate no longer kills in amounts of 2 units
Doubled metabolism rates.

This puts metabolism back between where it was originally, and where the metabolism rebalance put it. Thus it shouldn't break anything, but it'll make most chemicals a bit more usable.
Tajaran ear stuff, originally by chinsky

https://github.com/Baystation12/Baystation12/commit/79b17d0c1d2bcf3bd02ac17df027efe3be43d169
Merge branch 'master' of github.com:CIB/Baystation12
Changelog typo fix
Merge pull request #2236 from CIB/master

Metabolism fixes