Sync with source repo

[r03ert0]

---

• [ ] screenshot_test_walk generates the same test pictures as there were and does not show any errors
• [ ] These changes fix #__ (github issue number if applicable).
• [ ] All MicroDraw tools behave as expected:
  • GESTURES
    • [ ] zoom in and out with two finger drag works
  • KEYS
    • right and up arrow key or left and down arrow key
      • [ ] jump to next or previous slice respectively
      • [ ] update the slider accordingly
      • [ ] update the slice number accordingly
    • cmd z undoes
      • [ ] any step back that you have done in their chronological order including
      • [ ] translation of region
      • [ ] drawing region
      • [ ] adding point
      • [ ] deleting point to be completed (maybe it is implemented and working for all functions, so we can delete the single step checks)
  • TOOL BUTTONS
    • red rectangle in navigation window
      • [ ] corresponds to tissue piece selected in viewer
      • [ ] can be navigated upon mouse down drag
    • navigation tool
      • [ ] navigates the slice inside the viewer upon mouse down drag
    • home button
      • [ ] zooms out to view the data in full screen size view
    • zoomIn tool
      • [ ] zooms one step in upon click
    • zoomOut tool
      • [ ] zooms one step out upon click
    • left arrow
      • [ ] jumps to the previous slice
    • right arrow
      • [ ] jumps to the next slice
    • select tool
      • [ ] selects a region upon click
    • draw tool
      • [ ] draws a new region as bezier curve
    • drawPolygon tool
      • [x] draws a new region as a polygon path
    • simplify tool
      • [ ] decreases the number of points in the region path while aiming at conserving the shape
    • addPoint tool
      • [ ] adds a point to the path upon click at position of mouse click
    • deletePoint tool
      • [ ] deletes a point from the path upon mouse click
    • addRegion tool
      • [ ] unifies two overlapping regions into one
    • deleteRegion tool
      • [ ] deletes a region upon click
    • splitRegion tool
      • [ ] splits one region at the intersection path with a second region
    • rotate tool
      • [ ] rotates a region around the point of mouse click
    • flip tool
      • [ ] flips a region around its vertical axis
    • toPolygon tool
      • [ ] converts the region path from bezier curve to polygon path
    • toBezier
      • [ ] converts the region path from polygon path to bezier curve
    • copy tool
      • [ ] copies a region
    • paste tool
      • [ ] pastes the copied region
    • save tool
      • [ ] saves the set of drawn regions to the database
    • screenshot tool
      • [ ] creates a screenshot of the data layer (not of the annotations yet) at a chosen resolution
    • delete tool
      • [ ] deletes the selected region
    • closeMenu tool
      • [ ] hides the menu bar upon click
    • openMenu tool
      • [ ] shows the menu bar upon click
    • undo tool
      • [ ] undoes the user's actions in reverse chronological order

• [ ] I implemented tests for these changes OR
• [ ] These changes do not require tests because _____