COVID19_VIS

Update:

• A framework to combine vtk interactive windows to QT window, as in SubWindow class.
• A 3d volume rendering for lung part, needing masks as input. Result shown as below.
• Finished 2d views with interactions.
• Load data by UI, bugs here.
• Add a cropping box in 3d view.

Bugs:

• vtkNIFTIImageReader.SetInputData not working.
• Camera behaves weird after loading
• vtkBoxWidget doesn't work with vtkGenericRenderWindowInteractor while Qt doesn't work with vtkRenderWindowInteractor