fix up trace api, fix scenemanager holding onto objects that have been deleted
Added xAPI vocabulary definition placeholders
Merge branch 'development' of github.com:adlnet/Sandbox into development
update trace api
merge
add device orientation and stereo rendering
fix some missing files after cleanup
fix styles
remove some console warnings
fix path to locales after cleanup changes
Merge pull request #182 from NikolaySuslov/development

fix path to locales after cleanup changes
initial support for upload to 3dr proxy
add setting to control stereo rendering offset point
fix side panel resize functions
merge up development
add first support for 3d model upload. Clean up a bit. Add new asset type to support loading mesh as THREEjs buffergeometry to save memory. Not many downsides to this - maybe load all assets this way?
cherrypick 88fdb85
cherrypick 1901335
 cherry-pick ef727e7
cherrypick bd36369