Add multi-cursor support (#30)

* update execution of callExpressions

* tweak types to store multiple cursor ranges and hook up with artifact highlighting

* multi-cursor from 3d scene

Working but has to be capslock for the time being

* tweak pannel headers

* add issue to todo comment

src/lang/std/sketch.test.ts

@@ -118,7 +118,6 @@ show(mySketch001)`
       {
         mode: 'sketch',
         sketchMode: 'sketchEdit',
-        isTooltip: true,
         rotation: [0, 0, 0, 1],
         position: [0, 0, 0],
         pathToNode: ['body', 0, 'declarations', '0', 'init'],