How to store non-cuboid shapes in the maps

[hhirsch]

https://developer.valvesoftware.com/wiki/Valve_Map_Format

[ElementW]

Proposed XML wording for the current walls:

<solid>
  <position x="14.0" y="0.05" z="4.0"/>
  <shape type="cuboid" material="5">
    <scale x="4.4" y="0.2" z="4.4"/>
  </shape>
</solid>