Hydra Rendering and Stats

The Hydra is no longer squishy now that it doesn't use the G.Amoeba's
stats. It also isn't a living chain of numbers 1-3. Though with the new
duds, I'm considering lengthening it now. Looks kinda...stumpy.
Removed comments on hydra-stats
fix on-death for giant-amoeba

add-* functions return a map of the system and z, so you have to extract
the system when you're passing it further along.
add a message for giant amoeba splitting
spawn multiple large amoebas on giant amoeba death
move giant amoeba split rate to config.clj
can now change spawn rate just from giant_amoeba-split-rate in config.clj
add colossal amoeba
Hydra tweaks and boss-floor
Merge with Monster
Hydra tweaks

The Hydra is now four tiles long with the addition of hydra-rear. Also,
the hydra boss room has been changed to a desert for easier navigation.
We can turn it back to a maze on a further iteration, I just felt this
to be the quicker solution considering the sprint ends soon.
[DYSFUNCTIONAL] Merge with master

Merge with master. Game crashes upon attempting to spawn the Hydra's
tail it seems.
possible fix for hydra spawning
remove #_ so on-death is called
Merge branch 'master' of https://github.com/dunjeon-masters/dunjeon-crawler

Conflicts:
	desktop/src-common/rouje_like/config.clj