Modified extend to take into account primitive and absent values
Modified extend to take into account primitive and absent values

chenzlabs/aframe,googlecreativelab/aframe,weddingdj/aframe,mkungla/aframe,chenzlabs/aframe,darkwing/aframe,wizgrav/aframe,jaxmolina/ar,googlecreativelab/aframe,mkungla/aframe,dmarcos/aframe,darkwing/aframe,aframevr/aframe,aframevr/aframe,RSpace/aframe,ngokevin/aframe,wizgrav/aframe,weddingdj/aframe,ngokevin/aframe,RSpace/aframe,dmarcos/aframe,jaxmolina/ar