Started OSL emission.
Merge remote-tracking branch 'upstream/master' into OSL_emission
Experimenting with closure keywords.
Added EDF::evaluate_inputs, starting emission support.
Switched TLS to use operator[] instead of ().
Small cleanup.
Merge pull request #537 from est77/OSL_emission

OSL emission start
Fixed PR comments.
Merge branch 'master' into DisneyMaterial_optimization
Fixed PR comments.