* Add railing caps
-subtype of railing corners
* Batch of changes:
- Fixed cap sprite
- Added 2 more instances of caps (left and right)
- Added caps to rods crafting menu
- Changed cost of corner from 3 to 2
- Added cost to cap, it cost 2 rods
* Woops:
- Apparently railings corners and such borrow code from normal railing so they always drop 3 rods.
* Change railings to list
* removed density/climbable
- they inhert it from railing