Mouse cursor should show dashed and arrows

[edemaine]

We can improve the mouse cursors to show the new dashed and arrow state:

• [ ] Line segment can show dashed and arrow status
  • [ ] Arrowhead might need to be embedded directly in cursor, at least for local cursor
• [ ] Rectangle and ellipse can show dashed
  • [ ] Above dashing will require line segment, rectangle, and ellipse icons to be redone to be outline strokes instead of filled paths.
• [ ] Not sure about pen...