Add a create button which creates a new shape layer and allows the user to select areas by setting the mode to "ADD". Once the user is done selecting areas, they can click the same button to set the mode back to "PAN_ZOOM".
Handle when the user clicks to select areas for another layer.
Different colors for different shape layers.
The shape layers are saved to a new state dict mapping a field name to a shape layer after each layer change. The values of the dict are cleared and the annotation for that image is saved to the model when the user changes the image. When this happens, the area vertices are converted into a list of verticies to be saved into the csv file
Handle area annotations after annotation starts: