Fixes #6754.

All station pipes should again be properly layered when floor tiles are installed, etc.
Merge pull request #6760 from Zuhayr/master

Removes heist as a votable roundtype.
removing world debug message.
sanity check on facehuggers.
xenos need to hiss too
Merge pull request #6761 from DJSnapshot/hotfix

Xeno fixes and world debug message removal.
Fixes the missing right hand on the Xeno hunter.
Merge pull request #6758 from PsiOmegaDelta/ConsistentPipes

Fixes #6754.
Hotfix for broken damage reading
Merge pull request #6770 from Hubblenaut/master

Hotfix for broken damage reading
Merge branch 'master' of https://github.com/Baystation12/Baystation12
Fixes #6765
Fixes #6764
Fixes #6763
Fixes #6759
Fixes #6745
Fixes #6740
Fixes #6752
Fixes #6689
Fixes #6683