fix Getting Started > Builds buttons (for aframevr/aframe-site#265) (#1594)
fix Getting Started > Builds buttons (for aframevr/aframe-site#265) (#1594)

for
https://aframe.io/docs/0.1.0/guide/installation.html
https://aframe.io/docs/0.2.0/guide/getting-started.html
https://aframe.io/docs/master/guide/getting-started.html
fernandojsg/aframe,aframevr/aframe,googlecreativelab/aframe,ngokevin/aframe,wizgrav/aframe,mkungla/aframe,dmarcos/aframe,weddingdj/aframe,darkwing/aframe,chenzlabs/aframe,RSpace/aframe,aframevr/aframe,fernandojsg/aframe,mkungla/aframe,weddingdj/aframe,RSpace/aframe,jaxmolina/ar,dmarcos/aframe,wizgrav/aframe,darkwing/aframe,ngokevin/aframe,jaxmolina/ar,googlecreativelab/aframe,chenzlabs/aframe