Airlock Improvements - v0.5.0.110

Several improvements to airlocks. Airlocks now only link up and sync in rooms with 1 external airlock and 1 internal, with the room having no items. Dock overlay now only showing on external airlocks. When traders are now docked airlocks will show red indicating workers cannot pass.

Shields now reduce chance and damage to solar panels and connectors.

Help and tutorial updated.

Patches notes:-

• Airlock linking - simplify logic (1 external/1 internal/no items).
  
• Only show docking areas on external.
  
• Trader blocking airlock overlay red to indicate blocked movement.
  
• Custom music loading enabled.
  
• No external access message added.
  
• Fix: Worker jukebox usage - move off items even if jukebox in range.
  
• Fix: Airlock external check, test for external floor as well as empty.
  
• Fix: Draw dock - disable on internal airlocks.
  

Nick