Some tricks to avoid shadow artifacts: render back faces to shadow buffer,
use polygon offset.
Provide option to disable avatar shadowing.
Merge branch 'master' of https://github.com/highfidelity/hifi
What the heck; let's try using some multisampling on the shadow maps.
Merge branch 'master' of https://github.com/highfidelity/hifi
Merge pull request #2930 from ey6es/master

A couple tweaks to improve shadowing: render back faces into shadow map, use biased offset, add option to disable shadow on avatars.