WebXR Device API call agenda, Apr 2nd 2018

Squeaking in *just* under the 24hr-in-advance deadline. ;)

*Call Agenda Items:*

   - Representation of a rays in WebXR (#339
   <https://github.com/immersive-web/webxr/pull/339>)
   - Indicating how to render an input source model (#336
   <https://github.com/immersive-web/webxr/pull/336>)
   - Anchors as a core concept (#337
   <https://github.com/immersive-web/webxr/pull/337>)
   - Revisit Deferred Session creation (#256
   <https://github.com/immersive-web/webxr/pull/256>)

Please reply with any additional items you'd like to see addressed.

*Call date:* Tuesday April 2nd (and every other Tuesday thereafter)
*Call time:* 1:00 PM PST for one hour

WebEx call details are posted to the internal-webvr@w3.org mailing list,
accessible to any community group member.