Version 2.4.0

• Added comp_prop_rope_dynamic and comp_prop_cable_dynamic, for generating 3D ropes as dynamic props.
• Added comp_prop_rope_bunting, for positioning other props along a rope (could be used for lights, supports, decoration, etc).
• Prop ropes may optionally have a collision mesh.
• Added comp_propcombine_volume & tools/toolspropcombine, which allows specifing propcombine regions with brushwork.
  This does leave remmnants of the brush in the map, so the point entity may still need to be used if near brush limits.
• Added comp_vactube_spline, which generates Portal 2 vactube models following a path.
• Add an editor model for decals, like overlays have.
• Added ability to specify rotation seed for vactubes.