Mouthmuts prototype

Got no idea whether this works.  Haven't been able to compile since the
creature-rework.  Argh.
Merge pull request #5120 from KA101/MouthTentaclesEnabler

Mouthmuts prototype
Prevent empty log messages from being written.
Fixed error in slimed disease description.
Merge pull request #5130 from desrik/bugfix_slimed

Fixed error in slimed disease description.
Merge pull request #5129 from ianestrachan/no-empty-memorial-logs

Prevent empty log messages from being written.
Fix missing items in recipes and spawn lists
Another fix
Remove duplicate item spawn
Merge pull request #5132 from orzogc/fix-bugs

Fix missing items in recipes and spawn lists
Merge remote-tracking branch 'origin/master' into region_traits-ep01-the_quickening
region_settings: class not struct. derp.