Extracted model code from the WorkspaceView and rearranged it in a new model class. * WorkspaceModel.cpp/.h (new class): Model class for the workspace. * WorkspaceView.cpp/.h: Replaced QTreeWidget with QTreeView and removed model code. * OctaveLink.cpp/.h: Removed symbol table semaphore and methods to access the copy of the symbol table, removed copying the symbol table. * src.pro: Added new files to Qt project.