Continue track point button and other new features

[AnniekStok]

This branch contains several new features originally put together to customize the plugin to help a colleague with his use case. The new features include:

• A now (hopefully) bug free version of the 3D orthogonal views and 3D clipping plane views with following functionalities:
  orthogonal views:

  • syncing of the layer mode (brush/fill/pipet/navigate/select/add etc)
  • syncing of the layer data and addition/moving new points by clicking/dragging (if no TrackLabels are present)
  • syncing visibility of nodes
  • syncing node color aesthetics (colormap highlights, border color, size)
  • syncing selected_label
  • syncing redo/undo
  • syncing selecting nodes by clicking
  • optional cross widget that centers on the selected node

  clipping planes:

  • define a clipping plane range with a QRangeSlider on an Image or Labels layer
  • if there are tracks, the visible nodes in the TrackLabels and PointLabels will be filtered according to the clipping range specified on the layer in the dropdown.

• a radiobutton group to choose between 'continue tracks' vs 'start new tracks' when tracking with points (only visible if there is no TrackLabels together with TrackPoints).

• simplified treewidget range updates: when updating the selection, it checks if all those nodes are still in view. If not, autoRange() is called (instead of setting a customized range for the selected nodes, which is often zoomed in too far and not helpful).

• If you click outside a label or point in the TrackLabels or TrackPoints layer, the selected_nodes are reset.

• when you export to CSV, the node color and lineage are also included. The lineage_id is defined as the track_id of the earliest known predecessor (using the get_lineage_id function in SolutionTracks).

Note: in order to filter nodes in the clipping planes, I used the tracks_df dataframe that was originally on the treewidget. Instead, I moved it to the tracks_viewer in order to be able to use it elsewhere. Also, I needed a reference to the tracks_viewer in the run_viewer to be able to pass on the colormap when exporting to CSV.

I am keeping it in this draft pull request until we have settled on which of these features should go to main, and then I can add them separately.