Fixes #7233.

Making sure the skills list is always initiated, even when not created as a player mob.
Change the map file(s) that Travis checks, ensure it errors if one or more is not present
Merge pull request #7240 from GinjaNinja32/travis

Update Travis to check split map files
Encrpytion!

This misspelling was about to drive me insane.
Fixes invisible slimes
Fixes #7213 restoring unarmed damage to previous values, adjusts unarmed attack logs.

Unarmed attack messages no longer assume every attack verb ends with -ed.
Readds the atmos venting tower
Adjusts the nuke op shuttle prison cell
Merge pull request #7243 from mwerezak/h2h

Unarmed attacks
Merge pull request #7237 from PsiOmegaDelta/PunchTheKeysForGodsSake

Fixes #7233.
Merge pull request #7241 from GinjaNinja32/slimefix

Fixes invisible slimes.
Merge pull request #7248 from Baystation12/master

Master into dev.
Adds image for cult talismans

So they aren't blank when examined.
Fix num2hex()'s handling of zero
Merge pull request #7250 from GinjaNinja32/num2hex2

Fix num2hex()'s handling of zero
Readds the engine coolant replacement tvalve and splits the coolant loop into two pipenets again (allows for a pressure/temp difference).
Merge pull request #7249 from mwerezak/atmos-tower

Atmos tower, Nuke prison, talismans, engine
Fix for #7232.
Fix for #7204.
Merge pull request #7254 from Segrain/master

Bugfixes.