GRIM: Initialize animated pose to bind pose, so the model bounding box is calculated correctly. Fixes #1082

Also removed the yaw, pitch and roll fields from ModelNode as they are no longer needed after the rotation is converted to a quaternion.
GRIM: Initialize rotation quaternion also when loading text format model.
Merge pull request #1139 from Akz-/grim-elevator-fix

GRIM: Quaternion rotation fixes