TreeView and TemplateSelector added.
Renamed TryToGetChildCategory into GetChildCategory.
NestedClassesTemplateSelector -> LibraryTreeTemplateSelector
LibraryTreeTemplateSelector has been rewritten.
Merge pull request #102 from vmoyseenko/DUI-TemplateSelector(NestedClasses)

DUI: TreeView and TemplateSelector for NestedClasses added.