Fix quat not used inside composite

[boyazeno]

Motivation

composite object has parameter quat. But it is not actually used anywhere when create the objects. On the contrary, offset parameter are used as real off set to all sub objects. So with a reasonable guess, the quat should be also used to rotate each sub objects.

How to reproduce

Simply create a composite and assign a nontrivial quat, you will see no rotation is applied.

Fix

In this patch, an extra rotation is applied to each sub objects. Tests are added for simple checking.

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