Adding osl microfacet bsdf example scene.
Merge pull request #524 from est77/est

Adding osl microfacet bsdf example scene.
Object instance item changes color when assigning material

Until now the object instance item stayed pink when a material
was assigned. Now this issues has been solved and the style
is updated when a material is assigned through the
MaterialAssignmentEditorWindow.

Signed-off-by: Marius Avram <marius.avram1309@gmail.com>
Merge pull request #525 from marius-avram/pink_object_instance_item

Object instance item changes color when assigning material
Added expressions hash for later.
Removed crop region.
Removed un-needed label.
Fixed issues in find_path_in_searchpaths.
Fixed bug.