[DF-1404] Added initial realization of class
[DF-1404] Used MimeDataHelper2 at Scene tree
Merge branch 'feature-integration-new-materials' of https://github.com/dava/dava.framework into feature-integration-new-materials
Merge branch 'feature-integration-new-materials' of https://github.com/dava/dava.framework into feature-integration-new-materials
[DF-1404] Used mimedatahelper at SceneTabWidget
Merge branch 'feature-integration-new-materials' of https://github.com/dava/dava.framework into feature-integration-new-materials