Mesh split, bogeys follow rails.

Wow. This commit is too big. It:

* splits obj loaded meshes into individual named objects.
* moves obj to mesh(es) code into new file obj.impl.cpp, removing the
  clutter from mesh
* removes Physical for providing the wrong level of abstraction
* bit of a hack to adjust loaded models to offset rail vehicle bogeys to
  0 centre, and then applies their calculated position to the mesh

All in all, quite a lot of mess... But the result is the rail vehicle
bogeys now follow the rails quite authentically.

1 files changed, 1 insertions, 2 deletions

diff --git a/game/vehicles/vehicle.cpp b/game/vehicles/vehicle.cpp
index fceb37c..b9d10bc 100644
--- a/game/vehicles/vehicle.cpp
+++ b/game/vehicles/vehicle.cpp
@@ -4,8 +4,7 @@
 #include <memory>
 #include <utility>
 
-Vehicle::Vehicle(const LinkPtr & l, const std::string & obj, const std::string & tex) :
-	Physical(l->ends.front().first->pos, obj, tex)
+Vehicle::Vehicle(const LinkPtr & l, float ld) : linkDist {ld}
 {
 	linkHist.add(l, 0);
 }