Standardize official search path

[Roland Melkert]

MPD subfiles
Model Directory (the directory that the top-level model resides in)
<LDraw>\p
<LDraw>\parts
<LDraw>\models

I have no problem with this part (it basically just adds models to the spec.)

But I never really liked the following

<LDraw>\Unofficial\p
<LDraw>\Unofficial\parts

Because it breaks the 'package', also imho you should look in the unofficial location before the official one because part and primitives can be updated.
With the current order the old ones will still load.


I also would like to make clear this order is to be followed within the context of the currently begin processed ldraw file.

Meaning a stud.dat in the mpd's subfolder (or as a submodel) will not be used for each part in the scene.

It will only be used if it's actually referenced inside the mpd itself trough a "1 ..... stud.dat" line.

This because all references inside the mpd will be tested against the parent folder.

But once e.g. 3001.dat start loading it will look inside it's own folder (parts) first before going to the library p folder etc.

This will also ensure you can cache meshes.