change default text shader to sdf, as most non-stock font usage is likely to be sdf as per #2339
change default text shader to sdf, as most non-stock font usage is likely to be sdf as per #2339

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