All materials working with the comboBox. Coating material deleted.
Merge branch 'master' of github.com:tdmsolutions/mitsubarender

Conflicts:
	src/MitsubaRender/Exporter/MitsubaXml.cs
Merge branch 'master' of github.com:tdmsolutions/mitsubarender

Conflicts:
	src/MitsubaRender/Exporter/MitsubaXml.cs