Fixes and Improvements - v0.8.0.15

Just a roundup of fixes/improvements i've made over the xmas period. Main one being another improvement with pathing on/off items, as once an item is built, a worker should move off it, else it they are starting movement on an item. Also airlock areas should not function if the internal airlock door is broken (was previously only testing the external one).

Patch notes:-

• Improve: Worker building end building, move to a free spot if available.
  
• Improve: Worker direction when building, facing centre of item if larger than 1 tile
  
• Fix: Airlock areas should not function if internal airlock door is broken
  

Nick