Which shortcuts should be in our library and which not?

[Steffen]

I again disagree. My thoughts:
- having a wheel+tyre assembly is most useful when doing animations.
- having to dig out the fitting tyre for a wheel is tedious when building. having such a shortcut available is nice.
- the library anyway is cluttered with moved-to's and things, I cannot see a reason to drop the shortcuts. they are useful and don't hurt. if you don't like them - don't use them